Geometry Nodes: use virtual arrays in internal attribute api

A virtual array is a data structure that is similar to a normal array
in that its elements can be accessed by an index. However, a virtual
array does not have to be a contiguous array internally. Instead, its
elements can be layed out arbitrarily while element access happens
through a virtual function call. However, the virtual array data
structures are designed so that the virtual function call can be avoided
in cases where it could become a bottleneck.

Most commonly, a virtual array is backed by an actual array/span or
is a single value internally, that is the same for every index.
Besides those, there are many more specialized virtual arrays like the
ones that provides vertex positions based on the `MVert` struct or
vertex group weights.

Not all attributes used by geometry nodes are stored in simple contiguous
arrays. To provide uniform access to all kinds of attributes, the attribute
API has to provide virtual array functionality that hides the implementation
details of attributes.

Before this refactor, the attribute API provided its own virtual array
implementation as part of the `ReadAttribute` and `WriteAttribute` types.
That resulted in unnecessary code duplication with the virtual array system.
Even worse, it bound many algorithms used by geometry nodes to the specifics
of the attribute API, even though they could also use different data sources
(such as data from sockets, default values, later results of expressions, ...).

This refactor removes the `ReadAttribute` and `WriteAttribute` types and
replaces them with `GVArray` and `GVMutableArray` respectively. The `GV`
stands for "generic virtual". The "generic" means that the data type contained
in those virtual arrays is only known at run-time. There are the corresponding
statically typed types `VArray<T>` and `VMutableArray<T>` as well.

No regressions are expected from this refactor. It does come with one
improvement for users. The attribute API can convert the data type
on write now. This is especially useful when writing to builtin attributes
like `material_index` with e.g. the Attribute Math node (which usually
just writes to float attributes, while `material_index` is an integer attribute).

Differential Revision: https://developer.blender.org/D10994

5 files changed, 455 insertions, 832 deletions

diff --git a/source/blender/blenkernel/intern/attribute_access.cc b/source/blender/blenkernel/intern/attribute_access.cc
index ac582fc30e7..70572e446b7 100644
--- a/source/blender/blenkernel/intern/attribute_access.cc
+++ b/source/blender/blenkernel/intern/attribute_access.cc
@@ -44,196 +44,10 @@ using blender::float3;
 using blender::Set;
 using blender::StringRef;
 using blender::StringRefNull;
-using blender::bke::ReadAttributePtr;
-using blender::bke::WriteAttributePtr;
 using blender::fn::GMutableSpan;
 
 namespace blender::bke {
 
-/* -------------------------------------------------------------------- */
-/** \name Attribute Accessor implementations
- * \{ */
-
-ReadAttribute::~ReadAttribute()
-{
-  if (array_is_temporary_ && array_buffer_ != nullptr) {
-    cpp_type_.destruct_n(array_buffer_, size_);
-    MEM_freeN(array_buffer_);
-  }
-}
-
-fn::GSpan ReadAttribute::get_span() const
-{
-  if (size_ == 0) {
-    return fn::GSpan(cpp_type_);
-  }
-  if (array_buffer_ == nullptr) {
-    std::lock_guard lock{span_mutex_};
-    if (array_buffer_ == nullptr) {
-      this->initialize_span();
-    }
-  }
-  return fn::GSpan(cpp_type_, array_buffer_, size_);
-}
-
-void ReadAttribute::initialize_span() const
-{
-  const int element_size = cpp_type_.size();
-  array_buffer_ = MEM_mallocN_aligned(size_ * element_size, cpp_type_.alignment(), __func__);
-  array_is_temporary_ = true;
-  for (const int i : IndexRange(size_)) {
-    this->get_internal(i, POINTER_OFFSET(array_buffer_, i * element_size));
-  }
-}
-
-WriteAttribute::~WriteAttribute()
-{
-  if (array_should_be_applied_) {
-    CLOG_ERROR(&LOG, "Forgot to call apply_span.");
-  }
-  if (array_is_temporary_ && array_buffer_ != nullptr) {
-    cpp_type_.destruct_n(array_buffer_, size_);
-    MEM_freeN(array_buffer_);
-  }
-}
-
-/**
- * Get a mutable span that can be modified. When all modifications to the attribute are done,
- * #apply_span should be called. */
-fn::GMutableSpan WriteAttribute::get_span()
-{
-  if (size_ == 0) {
-    return fn::GMutableSpan(cpp_type_);
-  }
-  if (array_buffer_ == nullptr) {
-    this->initialize_span(false);
-  }
-  array_should_be_applied_ = true;
-  return fn::GMutableSpan(cpp_type_, array_buffer_, size_);
-}
-
-fn::GMutableSpan WriteAttribute::get_span_for_write_only()
-{
-  if (size_ == 0) {
-    return fn::GMutableSpan(cpp_type_);
-  }
-  if (array_buffer_ == nullptr) {
-    this->initialize_span(true);
-  }
-  array_should_be_applied_ = true;
-  return fn::GMutableSpan(cpp_type_, array_buffer_, size_);
-}
-
-void WriteAttribute::initialize_span(const bool write_only)
-{
-  const int element_size = cpp_type_.size();
-  array_buffer_ = MEM_mallocN_aligned(element_size * size_, cpp_type_.alignment(), __func__);
-  array_is_temporary_ = true;
-  if (write_only) {
-    /* This does nothing for trivial types, but is necessary for general correctness. */
-    cpp_type_.construct_default_n(array_buffer_, size_);
-  }
-  else {
-    for (const int i : IndexRange(size_)) {
-      this->get(i, POINTER_OFFSET(array_buffer_, i * element_size));
-    }
-  }
-}
-
-void WriteAttribute::apply_span()
-{
-  this->apply_span_if_necessary();
-  array_should_be_applied_ = false;
-}
-
-void WriteAttribute::apply_span_if_necessary()
-{
-  /* Only works when the span has been initialized beforehand. */
-  BLI_assert(array_buffer_ != nullptr);
-
-  const int element_size = cpp_type_.size();
-  for (const int i : IndexRange(size_)) {
-    this->set_internal(i, POINTER_OFFSET(array_buffer_, i * element_size));
-  }
-}
-
-/* This is used by the #OutputAttributePtr class. */
-class TemporaryWriteAttribute final : public WriteAttribute {
- public:
-  GMutableSpan data;
-  GeometryComponent &component;
-  std::string final_name;
-
-  TemporaryWriteAttribute(AttributeDomain domain,
-                          GMutableSpan data,
-                          GeometryComponent &component,
-                          std::string final_name)
-      : WriteAttribute(domain, data.type(), data.size()),
-        data(data),
-        component(component),
-        final_name(std::move(final_name))
-  {
-  }
-
-  ~TemporaryWriteAttribute() override
-  {
-    if (data.data() != nullptr) {
-      cpp_type_.destruct_n(data.data(), data.size());
-      MEM_freeN(data.data());
-    }
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    data.type().copy_to_uninitialized(data[index], r_value);
-  }
-
-  void set_internal(const int64_t index, const void *value) override
-  {
-    data.type().copy_to_initialized(value, data[index]);
-  }
-
-  void initialize_span(const bool UNUSED(write_only)) override
-  {
-    array_buffer_ = data.data();
-    array_is_temporary_ = false;
-  }
-
-  void apply_span_if_necessary() override
-  {
-    /* Do nothing, because the span contains the attribute itself already. */
-  }
-};
-
-class ConvertedReadAttribute final : public ReadAttribute {
- private:
-  const CPPType &from_type_;
-  const CPPType &to_type_;
-  ReadAttributePtr base_attribute_;
-  void (*convert_)(const void *src, void *dst);
-
- public:
-  ConvertedReadAttribute(ReadAttributePtr base_attribute, const CPPType &to_type)
-      : ReadAttribute(base_attribute->domain(), to_type, base_attribute->size()),
-        from_type_(base_attribute->cpp_type()),
-        to_type_(to_type),
-        base_attribute_(std::move(base_attribute))
-  {
-    const nodes::DataTypeConversions &conversions = nodes::get_implicit_type_conversions();
-    convert_ = conversions.get_conversion_functions(base_attribute_->cpp_type(), to_type)
-                   ->convert_single_to_uninitialized;
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    BUFFER_FOR_CPP_TYPE_VALUE(from_type_, buffer);
-    base_attribute_->get(index, buffer);
-    convert_(buffer, r_value);
-  }
-};
-
-/** \} */
-
 const blender::fn::CPPType *custom_data_type_to_cpp_type(const CustomDataType type)
 {
   switch (type) {
@@ -368,7 +182,17 @@ AttributeDomain attribute_domain_highest_priority(Span<AttributeDomain> domains)
   return highest_priority_domain;
 }
 
-ReadAttributePtr BuiltinCustomDataLayerProvider::try_get_for_read(
+void OutputAttribute::save()
+{
+  if (optional_span_varray_.has_value()) {
+    optional_span_varray_->save();
+  }
+  if (save_) {
+    save_(*this);
+  }
+}
+
+GVArrayPtr BuiltinCustomDataLayerProvider::try_get_for_read(
     const GeometryComponent &component) const
 {
   const CustomData *custom_data = custom_data_access_.get_const_custom_data(component);
@@ -384,7 +208,7 @@ ReadAttributePtr BuiltinCustomDataLayerProvider::try_get_for_read(
   return as_read_attribute_(data, domain_size);
 }
 
-WriteAttributePtr BuiltinCustomDataLayerProvider::try_get_for_write(
+GVMutableArrayPtr BuiltinCustomDataLayerProvider::try_get_for_write(
     GeometryComponent &component) const
 {
   if (writable_ != Writable) {
@@ -463,7 +287,7 @@ bool BuiltinCustomDataLayerProvider::exists(const GeometryComponent &component)
   return data != nullptr;
 }
 
-ReadAttributePtr CustomDataAttributeProvider::try_get_for_read(
+ReadAttributeLookup CustomDataAttributeProvider::try_get_for_read(
     const GeometryComponent &component, const StringRef attribute_name) const
 {
   const CustomData *custom_data = custom_data_access_.get_const_custom_data(component);
@@ -496,7 +320,7 @@ ReadAttributePtr CustomDataAttributeProvider::try_get_for_read(
   return {};
 }
 
-WriteAttributePtr CustomDataAttributeProvider::try_get_for_write(
+WriteAttributeLookup CustomDataAttributeProvider::try_get_for_write(
     GeometryComponent &component, const StringRef attribute_name) const
 {
   CustomData *custom_data = custom_data_access_.get_custom_data(component);
@@ -595,7 +419,7 @@ bool CustomDataAttributeProvider::foreach_attribute(const GeometryComponent &com
   return true;
 }
 
-ReadAttributePtr NamedLegacyCustomDataProvider::try_get_for_read(
+ReadAttributeLookup NamedLegacyCustomDataProvider::try_get_for_read(
     const GeometryComponent &component, const StringRef attribute_name) const
 {
   const CustomData *custom_data = custom_data_access_.get_const_custom_data(component);
@@ -606,14 +430,14 @@ ReadAttributePtr NamedLegacyCustomDataProvider::try_get_for_read(
     if (layer.type == stored_type_) {
       if (layer.name == attribute_name) {
         const int domain_size = component.attribute_domain_size(domain_);
-        return as_read_attribute_(layer.data, domain_size);
+        return {as_read_attribute_(layer.data, domain_size), domain_};
       }
     }
   }
   return {};
 }
 
-WriteAttributePtr NamedLegacyCustomDataProvider::try_get_for_write(
+WriteAttributeLookup NamedLegacyCustomDataProvider::try_get_for_write(
     GeometryComponent &component, const StringRef attribute_name) const
 {
   CustomData *custom_data = custom_data_access_.get_custom_data(component);
@@ -630,7 +454,7 @@ WriteAttributePtr NamedLegacyCustomDataProvider::try_get_for_write(
         if (data_old != data_new) {
           custom_data_access_.update_custom_data_pointers(component);
         }
-        return as_write_attribute_(layer.data, domain_size);
+        return {as_write_attribute_(layer.data, domain_size), domain_};
       }
     }
   }
@@ -708,7 +532,17 @@ int GeometryComponent::attribute_domain_size(const AttributeDomain UNUSED(domain
   return 0;
 }
 
-ReadAttributePtr GeometryComponent::attribute_try_get_for_read(
+bool GeometryComponent::attribute_is_builtin(const blender::StringRef attribute_name) const
+{
+  using namespace blender::bke;
+  const ComponentAttributeProviders *providers = this->get_attribute_providers();
+  if (providers == nullptr) {
+    return false;
+  }
+  return providers->builtin_attribute_providers().contains_as(attribute_name);
+}
+
+blender::bke::ReadAttributeLookup GeometryComponent::attribute_try_get_for_read(
     const StringRef attribute_name) const
 {
   using namespace blender::bke;
@@ -719,11 +553,11 @@ ReadAttributePtr GeometryComponent::attribute_try_get_for_read(
   const BuiltinAttributeProvider *builtin_provider =
       providers->builtin_attribute_providers().lookup_default_as(attribute_name, nullptr);
   if (builtin_provider != nullptr) {
-    return builtin_provider->try_get_for_read(*this);
+    return {builtin_provider->try_get_for_read(*this), builtin_provider->domain()};
   }
   for (const DynamicAttributesProvider *dynamic_provider :
        providers->dynamic_attribute_providers()) {
-    ReadAttributePtr attribute = dynamic_provider->try_get_for_read(*this, attribute_name);
+    ReadAttributeLookup attribute = dynamic_provider->try_get_for_read(*this, attribute_name);
     if (attribute) {
       return attribute;
     }
@@ -731,16 +565,19 @@ ReadAttributePtr GeometryComponent::attribute_try_get_for_read(
   return {};
 }
 
-ReadAttributePtr GeometryComponent::attribute_try_adapt_domain(
-    ReadAttributePtr attribute, const AttributeDomain new_domain) const
+std::unique_ptr<blender::fn::GVArray> GeometryComponent::attribute_try_adapt_domain(
+    std::unique_ptr<blender::fn::GVArray> varray,
+    const AttributeDomain from_domain,
+    const AttributeDomain to_domain) const
 {
-  if (attribute && attribute->domain() == new_domain) {
-    return attribute;
+  if (from_domain == to_domain) {
+    return varray;
   }
   return {};
 }
 
-WriteAttributePtr GeometryComponent::attribute_try_get_for_write(const StringRef attribute_name)
+blender::bke::WriteAttributeLookup GeometryComponent::attribute_try_get_for_write(
+    const StringRef attribute_name)
 {
   using namespace blender::bke;
   const ComponentAttributeProviders *providers = this->get_attribute_providers();
@@ -750,11 +587,11 @@ WriteAttributePtr GeometryComponent::attribute_try_get_for_write(const StringRef
   const BuiltinAttributeProvider *builtin_provider =
       providers->builtin_attribute_providers().lookup_default_as(attribute_name, nullptr);
   if (builtin_provider != nullptr) {
-    return builtin_provider->try_get_for_write(*this);
+    return {builtin_provider->try_get_for_write(*this), builtin_provider->domain()};
   }
   for (const DynamicAttributesProvider *dynamic_provider :
        providers->dynamic_attribute_providers()) {
-    WriteAttributePtr attribute = dynamic_provider->try_get_for_write(*this, attribute_name);
+    WriteAttributeLookup attribute = dynamic_provider->try_get_for_write(*this, attribute_name);
     if (attribute) {
       return attribute;
     }
@@ -814,6 +651,24 @@ bool GeometryComponent::attribute_try_create(const StringRef attribute_name,
   return false;
 }
 
+bool GeometryComponent::attribute_try_create_builtin(const blender::StringRef attribute_name)
+{
+  using namespace blender::bke;
+  if (attribute_name.is_empty()) {
+    return false;
+  }
+  const ComponentAttributeProviders *providers = this->get_attribute_providers();
+  if (providers == nullptr) {
+    return false;
+  }
+  const BuiltinAttributeProvider *builtin_provider =
+      providers->builtin_attribute_providers().lookup_default_as(attribute_name, nullptr);
+  if (builtin_provider == nullptr) {
+    return false;
+  }
+  return builtin_provider->try_create(*this);
+}
+
 Set<std::string> GeometryComponent::attribute_names() const
 {
   Set<std::string> attributes;
@@ -867,264 +722,234 @@ bool GeometryComponent::attribute_foreach(const AttributeForeachCallback callbac
 
 bool GeometryComponent::attribute_exists(const blender::StringRef attribute_name) const
 {
-  ReadAttributePtr attribute = this->attribute_try_get_for_read(attribute_name);
+  blender::bke::ReadAttributeLookup attribute = this->attribute_try_get_for_read(attribute_name);
   if (attribute) {
     return true;
   }
   return false;
 }
 
-static ReadAttributePtr try_adapt_data_type(ReadAttributePtr attribute,
-                                            const blender::fn::CPPType &to_type)
+static std::unique_ptr<blender::fn::GVArray> try_adapt_data_type(
+    std::unique_ptr<blender::fn::GVArray> varray, const blender::fn::CPPType &to_type)
 {
-  const blender::fn::CPPType &from_type = attribute->cpp_type();
-  if (from_type == to_type) {
-    return attribute;
-  }
-
   const blender::nodes::DataTypeConversions &conversions =
       blender::nodes::get_implicit_type_conversions();
-  if (!conversions.is_convertible(from_type, to_type)) {
-    return {};
-  }
-
-  return std::make_unique<blender::bke::ConvertedReadAttribute>(std::move(attribute), to_type);
+  return conversions.try_convert(std::move(varray), to_type);
 }
 
-ReadAttributePtr GeometryComponent::attribute_try_get_for_read(
+std::unique_ptr<blender::fn::GVArray> GeometryComponent::attribute_try_get_for_read(
     const StringRef attribute_name,
     const AttributeDomain domain,
     const CustomDataType data_type) const
 {
-  ReadAttributePtr attribute = this->attribute_try_get_for_read(attribute_name);
+  blender::bke::ReadAttributeLookup attribute = this->attribute_try_get_for_read(attribute_name);
   if (!attribute) {
     return {};
   }
 
-  if (domain != ATTR_DOMAIN_AUTO && attribute->domain() != domain) {
-    attribute = this->attribute_try_adapt_domain(std::move(attribute), domain);
-    if (!attribute) {
+  std::unique_ptr<blender::fn::GVArray> varray = std::move(attribute.varray);
+  if (domain != ATTR_DOMAIN_AUTO && attribute.domain != domain) {
+    varray = this->attribute_try_adapt_domain(std::move(varray), attribute.domain, domain);
+    if (!varray) {
       return {};
     }
   }
 
   const blender::fn::CPPType *cpp_type = blender::bke::custom_data_type_to_cpp_type(data_type);
   BLI_assert(cpp_type != nullptr);
-  if (attribute->cpp_type() != *cpp_type) {
-    attribute = try_adapt_data_type(std::move(attribute), *cpp_type);
-    if (!attribute) {
+  if (varray->type() != *cpp_type) {
+    varray = try_adapt_data_type(std::move(varray), *cpp_type);
+    if (!varray) {
       return {};
     }
   }
 
-  return attribute;
+  return varray;
 }
 
-ReadAttributePtr GeometryComponent::attribute_try_get_for_read(const StringRef attribute_name,
-                                                               const AttributeDomain domain) const
+std::unique_ptr<blender::bke::GVArray> GeometryComponent::attribute_try_get_for_read(
+    const StringRef attribute_name, const AttributeDomain domain) const
 {
   if (!this->attribute_domain_supported(domain)) {
     return {};
   }
 
-  ReadAttributePtr attribute = this->attribute_try_get_for_read(attribute_name);
+  blender::bke::ReadAttributeLookup attribute = this->attribute_try_get_for_read(attribute_name);
   if (!attribute) {
     return {};
   }
 
-  if (attribute->domain() != domain) {
-    attribute = this->attribute_try_adapt_domain(std::move(attribute), domain);
-    if (!attribute) {
-      return {};
-    }
+  if (attribute.domain != domain) {
+    return this->attribute_try_adapt_domain(std::move(attribute.varray), attribute.domain, domain);
   }
 
-  return attribute;
+  return std::move(attribute.varray);
 }
 
-ReadAttributePtr GeometryComponent::attribute_get_for_read(const StringRef attribute_name,
-                                                           const AttributeDomain domain,
-                                                           const CustomDataType data_type,
-                                                           const void *default_value) const
-{
-  ReadAttributePtr attribute = this->attribute_try_get_for_read(attribute_name, domain, data_type);
-  if (attribute) {
-    return attribute;
-  }
-  return this->attribute_get_constant_for_read(domain, data_type, default_value);
-}
-
-blender::bke::ReadAttributePtr GeometryComponent::attribute_get_constant_for_read(
-    const AttributeDomain domain, const CustomDataType data_type, const void *value) const
-{
-  BLI_assert(this->attribute_domain_supported(domain));
-  const blender::fn::CPPType *cpp_type = blender::bke::custom_data_type_to_cpp_type(data_type);
-  BLI_assert(cpp_type != nullptr);
-  if (value == nullptr) {
-    value = cpp_type->default_value();
-  }
-  const int domain_size = this->attribute_domain_size(domain);
-  return std::make_unique<blender::bke::ConstantReadAttribute>(
-      domain, domain_size, *cpp_type, value);
-}
-
-blender::bke::ReadAttributePtr GeometryComponent::attribute_get_constant_for_read_converted(
+std::unique_ptr<blender::bke::GVArray> GeometryComponent::attribute_get_for_read(
+    const StringRef attribute_name,
     const AttributeDomain domain,
-    const CustomDataType in_data_type,
-    const CustomDataType out_data_type,
-    const void *value) const
+    const CustomDataType data_type,
+    const void *default_value) const
 {
-  BLI_assert(this->attribute_domain_supported(domain));
-  if (value == nullptr || in_data_type == out_data_type) {
-    return this->attribute_get_constant_for_read(domain, out_data_type, value);
+  std::unique_ptr<blender::bke::GVArray> varray = this->attribute_try_get_for_read(
+      attribute_name, domain, data_type);
+  if (varray) {
+    return varray;
+  }
+  const blender::fn::CPPType *type = blender::bke::custom_data_type_to_cpp_type(data_type);
+  if (default_value == nullptr) {
+    default_value = type->default_value();
   }
-
-  const blender::fn::CPPType *in_cpp_type = blender::bke::custom_data_type_to_cpp_type(
-      in_data_type);
-  const blender::fn::CPPType *out_cpp_type = blender::bke::custom_data_type_to_cpp_type(
-      out_data_type);
-  BLI_assert(in_cpp_type != nullptr);
-  BLI_assert(out_cpp_type != nullptr);
-
-  const blender::nodes::DataTypeConversions &conversions =
-      blender::nodes::get_implicit_type_conversions();
-  BLI_assert(conversions.is_convertible(*in_cpp_type, *out_cpp_type));
-
-  void *out_value = alloca(out_cpp_type->size());
-  conversions.convert_to_uninitialized(*in_cpp_type, *out_cpp_type, value, out_value);
-
   const int domain_size = this->attribute_domain_size(domain);
-  blender::bke::ReadAttributePtr attribute = std::make_unique<blender::bke::ConstantReadAttribute>(
-      domain, domain_size, *out_cpp_type, out_value);
-
-  out_cpp_type->destruct(out_value);
-  return attribute;
+  return std::make_unique<blender::fn::GVArray_For_SingleValue>(*type, domain_size, default_value);
 }
 
-OutputAttributePtr GeometryComponent::attribute_try_get_for_output(const StringRef attribute_name,
-                                                                   const AttributeDomain domain,
-                                                                   const CustomDataType data_type,
-                                                                   const void *default_value)
-{
-  const blender::fn::CPPType *cpp_type = blender::bke::custom_data_type_to_cpp_type(data_type);
-  BLI_assert(cpp_type != nullptr);
-
-  WriteAttributePtr attribute = this->attribute_try_get_for_write(attribute_name);
+class GVMutableAttribute_For_OutputAttribute
+    : public blender::fn::GVMutableArray_For_GMutableSpan {
+ public:
+  GeometryComponent *component;
+  std::string final_name;
 
-  /* If the attribute doesn't exist, make a new one with the correct type. */
-  if (!attribute) {
-    this->attribute_try_create(attribute_name, domain, data_type);
-    attribute = this->attribute_try_get_for_write(attribute_name);
-    if (attribute && default_value != nullptr) {
-      void *data = attribute->get_span_for_write_only().data();
-      cpp_type->fill_initialized(default_value, data, attribute->size());
-      attribute->apply_span();
-    }
-    return OutputAttributePtr(std::move(attribute));
+  GVMutableAttribute_For_OutputAttribute(GMutableSpan data,
+                                         GeometryComponent &component,
+                                         std::string final_name)
+      : blender::fn::GVMutableArray_For_GMutableSpan(data),
+        component(&component),
+        final_name(std::move(final_name))
+  {
   }
 
-  /* If an existing attribute has a matching domain and type, just use that. */
-  if (attribute->domain() == domain && attribute->cpp_type() == *cpp_type) {
-    return OutputAttributePtr(std::move(attribute));
+  ~GVMutableAttribute_For_OutputAttribute() override
+  {
+    type_->destruct_n(data_, size_);
+    MEM_freeN(data_);
   }
+};
 
-  /* Otherwise create a temporary buffer to use before saving the new attribute. */
-  return OutputAttributePtr(*this, domain, attribute_name, data_type);
-}
-
-/* Construct from an attribute that already exists in the geometry component. */
-OutputAttributePtr::OutputAttributePtr(WriteAttributePtr attribute)
-    : attribute_(std::move(attribute))
+static void save_output_attribute(blender::bke::OutputAttribute &output_attribute)
 {
-}
+  using namespace blender;
+  using namespace blender::fn;
+  using namespace blender::bke;
 
-/* Construct a temporary attribute that has to replace an existing one later on. */
-OutputAttributePtr::OutputAttributePtr(GeometryComponent &component,
-                                       AttributeDomain domain,
-                                       std::string final_name,
-                                       CustomDataType data_type)
-{
-  const blender::fn::CPPType *cpp_type = blender::bke::custom_data_type_to_cpp_type(data_type);
-  BLI_assert(cpp_type != nullptr);
+  GVMutableAttribute_For_OutputAttribute &varray =
+      dynamic_cast<GVMutableAttribute_For_OutputAttribute &>(output_attribute.varray());
 
-  const int domain_size = component.attribute_domain_size(domain);
-  void *buffer = MEM_malloc_arrayN(domain_size, cpp_type->size(), __func__);
-  GMutableSpan new_span{*cpp_type, buffer, domain_size};
+  GeometryComponent &component = *varray.component;
+  const StringRefNull name = varray.final_name;
+  const AttributeDomain domain = output_attribute.domain();
+  const CustomDataType data_type = output_attribute.custom_data_type();
+  const CPPType &cpp_type = output_attribute.cpp_type();
 
-  /* Copy converted values from conflicting attribute, in case the value is read.
-   * TODO: An optimization could be to not do this, when the caller says that the attribute will
-   * only be written. */
-  ReadAttributePtr src_attribute = component.attribute_get_for_read(
-      final_name, domain, data_type, nullptr);
-  for (const int i : blender::IndexRange(domain_size)) {
-    src_attribute->get(i, new_span[i]);
+  component.attribute_try_delete(name);
+  if (!component.attribute_try_create(varray.final_name, domain, data_type)) {
+    CLOG_WARN(&LOG,
+              "Could not create the '%s' attribute with type '%s'.",
+              name.c_str(),
+              cpp_type.name().c_str());
+    return;
+  }
+  WriteAttributeLookup write_attribute = component.attribute_try_get_for_write(name);
+  BUFFER_FOR_CPP_TYPE_VALUE(varray.type(), buffer);
+  for (const int i : IndexRange(varray.size())) {
+    varray.get(i, buffer);
+    write_attribute.varray->set_by_relocate(i, buffer);
   }
-
-  attribute_ = std::make_unique<blender::bke::TemporaryWriteAttribute>(
-      domain, new_span, component, std::move(final_name));
 }
 
-/* Store the computed attribute. If it was stored from the beginning already, nothing is done. This
- * might delete another attribute with the same name. */
-void OutputAttributePtr::save()
+static blender::bke::OutputAttribute create_output_attribute(
+    GeometryComponent &component,
+    const blender::StringRef attribute_name,
+    const AttributeDomain domain,
+    const CustomDataType data_type,
+    const bool ignore_old_values,
+    const void *default_value)
 {
-  if (!attribute_) {
-    CLOG_WARN(&LOG, "Trying to save an attribute that does not exist anymore.");
-    return;
-  }
-
-  blender::bke::TemporaryWriteAttribute *attribute =
-      dynamic_cast<blender::bke::TemporaryWriteAttribute *>(attribute_.get());
+  using namespace blender;
+  using namespace blender::fn;
+  using namespace blender::bke;
 
-  if (attribute == nullptr) {
-    /* The attribute is saved already. */
-    attribute_.reset();
-    return;
+  if (attribute_name.is_empty()) {
+    return {};
   }
 
-  StringRefNull name = attribute->final_name;
-  const blender::fn::CPPType &cpp_type = attribute->cpp_type();
-
-  /* Delete an existing attribute with the same name if necessary. */
-  attribute->component.attribute_try_delete(name);
+  const CPPType *cpp_type = custom_data_type_to_cpp_type(data_type);
+  BLI_assert(cpp_type != nullptr);
+  const nodes::DataTypeConversions &conversions = nodes::get_implicit_type_conversions();
 
-  if (!attribute->component.attribute_try_create(
-          name, attribute_->domain(), attribute_->custom_data_type())) {
-    /* Cannot create the target attribute for some reason. */
-    CLOG_WARN(&LOG,
-              "Creating the '%s' attribute with type '%s' failed.",
-              name.c_str(),
-              cpp_type.name().c_str());
-    attribute_.reset();
-    return;
+  if (component.attribute_is_builtin(attribute_name)) {
+    WriteAttributeLookup attribute = component.attribute_try_get_for_write(attribute_name);
+    if (!attribute) {
+      component.attribute_try_create_builtin(attribute_name);
+      attribute = component.attribute_try_get_for_write(attribute_name);
+      if (!attribute) {
+        /* Builtin attribute does not exist and can't be created. */
+        return {};
+      }
+    }
+    if (attribute.domain != domain) {
+      /* Builtin attribute is on different domain. */
+      return {};
+    }
+    GVMutableArrayPtr varray = std::move(attribute.varray);
+    if (varray->type() == *cpp_type) {
+      /* Builtin attribute matches exactly. */
+      return OutputAttribute(std::move(varray), domain, {}, ignore_old_values);
+    }
+    /* Builtin attribute is on the same domain but has a different data type. */
+    varray = conversions.try_convert(std::move(varray), *cpp_type);
+    return OutputAttribute(std::move(varray), domain, {}, ignore_old_values);
   }
 
-  WriteAttributePtr new_attribute = attribute->component.attribute_try_get_for_write(name);
-
-  GMutableSpan temp_span = attribute->data;
-  GMutableSpan new_span = new_attribute->get_span_for_write_only();
-  BLI_assert(temp_span.size() == new_span.size());
+  WriteAttributeLookup attribute = component.attribute_try_get_for_write(attribute_name);
+  if (!attribute) {
+    component.attribute_try_create(attribute_name, domain, data_type);
+    attribute = component.attribute_try_get_for_write(attribute_name);
+    if (!attribute) {
+      /* Can't create the attribute. */
+      return {};
+    }
+  }
+  if (attribute.domain == domain && attribute.varray->type() == *cpp_type) {
+    /* Existing generic attribute matches exactly. */
+    return OutputAttribute(std::move(attribute.varray), domain, {}, ignore_old_values);
+  }
 
-  /* Currently we copy over the attribute. In the future we want to reuse the buffer. */
-  cpp_type.move_to_initialized_n(temp_span.data(), new_span.data(), new_span.size());
-  new_attribute->apply_span();
+  const int domain_size = component.attribute_domain_size(domain);
+  /* Allocate a new array that lives next to the existing attribute. It will overwrite the existing
+   * attribute after processing is done. */
+  void *data = MEM_mallocN_aligned(
+      cpp_type->size() * domain_size, cpp_type->alignment(), __func__);
+  if (ignore_old_values) {
+    /* This does nothing for trivially constructible types, but is necessary for correctness. */
+    cpp_type->construct_default_n(data, domain);
+  }
+  else {
+    /* Fill the temporary array with values from the existing attribute. */
+    GVArrayPtr old_varray = component.attribute_get_for_read(
+        attribute_name, domain, data_type, default_value);
+    old_varray->materialize_to_uninitialized(IndexRange(domain_size), data);
+  }
+  GVMutableArrayPtr varray = std::make_unique<GVMutableAttribute_For_OutputAttribute>(
+      GMutableSpan{*cpp_type, data, domain_size}, component, attribute_name);
 
-  attribute_.reset();
+  return OutputAttribute(std::move(varray), domain, save_output_attribute, true);
 }
 
-OutputAttributePtr::~OutputAttributePtr()
+blender::bke::OutputAttribute GeometryComponent::attribute_try_get_for_output(
+    const StringRef attribute_name,
+    const AttributeDomain domain,
+    const CustomDataType data_type,
+    const void *default_value)
 {
-  if (attribute_) {
-    CLOG_ERROR(&LOG, "Forgot to call #save or #apply_span_and_save.");
-  }
+  return create_output_attribute(*this, attribute_name, domain, data_type, false, default_value);
 }
 
-/* Utility function to call #apply_span and #save in the right order. */
-void OutputAttributePtr::apply_span_and_save()
+blender::bke::OutputAttribute GeometryComponent::attribute_try_get_for_output_only(
+    const blender::StringRef attribute_name,
+    const AttributeDomain domain,
+    const CustomDataType data_type)
 {
-  BLI_assert(attribute_);
-  attribute_->apply_span();
-  this->save();
+  return create_output_attribute(*this, attribute_name, domain, data_type, true, nullptr);
 }
-
-/** \} */
diff --git a/source/blender/blenkernel/intern/attribute_access_intern.hh b/source/blender/blenkernel/intern/attribute_access_intern.hh
index 806d10e9e89..7cf585dfbfc 100644
--- a/source/blender/blenkernel/intern/attribute_access_intern.hh
+++ b/source/blender/blenkernel/intern/attribute_access_intern.hh
@@ -24,166 +24,8 @@
 
 namespace blender::bke {
 
-class ConstantReadAttribute final : public ReadAttribute {
- private:
-  void *value_;
-
- public:
-  ConstantReadAttribute(AttributeDomain domain,
-                        const int64_t size,
-                        const CPPType &type,
-                        const void *value)
-      : ReadAttribute(domain, type, size)
-  {
-    value_ = MEM_mallocN_aligned(type.size(), type.alignment(), __func__);
-    type.copy_to_uninitialized(value, value_);
-  }
-
-  ~ConstantReadAttribute() override
-  {
-    this->cpp_type_.destruct(value_);
-    MEM_freeN(value_);
-  }
-
-  void get_internal(const int64_t UNUSED(index), void *r_value) const override
-  {
-    this->cpp_type_.copy_to_uninitialized(value_, r_value);
-  }
-
-  void initialize_span() const override
-  {
-    const int element_size = cpp_type_.size();
-    array_buffer_ = MEM_mallocN_aligned(size_ * element_size, cpp_type_.alignment(), __func__);
-    array_is_temporary_ = true;
-    cpp_type_.fill_uninitialized(value_, array_buffer_, size_);
-  }
-};
-
-template<typename T> class ArrayReadAttribute final : public ReadAttribute {
- private:
-  Span<T> data_;
-
- public:
-  ArrayReadAttribute(AttributeDomain domain, Span<T> data)
-      : ReadAttribute(domain, CPPType::get<T>(), data.size()), data_(data)
-  {
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    new (r_value) T(data_[index]);
-  }
-
-  void initialize_span() const override
-  {
-    /* The data will not be modified, so this const_cast is fine. */
-    array_buffer_ = const_cast<T *>(data_.data());
-    array_is_temporary_ = false;
-  }
-};
-
-template<typename T> class OwnedArrayReadAttribute final : public ReadAttribute {
- private:
-  Array<T> data_;
-
- public:
-  OwnedArrayReadAttribute(AttributeDomain domain, Array<T> data)
-      : ReadAttribute(domain, CPPType::get<T>(), data.size()), data_(std::move(data))
-  {
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    new (r_value) T(data_[index]);
-  }
-
-  void initialize_span() const override
-  {
-    /* The data will not be modified, so this const_cast is fine. */
-    array_buffer_ = const_cast<T *>(data_.data());
-    array_is_temporary_ = false;
-  }
-};
-
-template<typename StructT, typename ElemT, ElemT (*GetFunc)(const StructT &)>
-class DerivedArrayReadAttribute final : public ReadAttribute {
- private:
-  Span<StructT> data_;
-
- public:
-  DerivedArrayReadAttribute(AttributeDomain domain, Span<StructT> data)
-      : ReadAttribute(domain, CPPType::get<ElemT>(), data.size()), data_(data)
-  {
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    const StructT &struct_value = data_[index];
-    const ElemT value = GetFunc(struct_value);
-    new (r_value) ElemT(value);
-  }
-};
-
-template<typename T> class ArrayWriteAttribute final : public WriteAttribute {
- private:
-  MutableSpan<T> data_;
-
- public:
-  ArrayWriteAttribute(AttributeDomain domain, MutableSpan<T> data)
-      : WriteAttribute(domain, CPPType::get<T>(), data.size()), data_(data)
-  {
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    new (r_value) T(data_[index]);
-  }
-
-  void set_internal(const int64_t index, const void *value) override
-  {
-    data_[index] = *reinterpret_cast<const T *>(value);
-  }
-
-  void initialize_span(const bool UNUSED(write_only)) override
-  {
-    array_buffer_ = data_.data();
-    array_is_temporary_ = false;
-  }
-
-  void apply_span_if_necessary() override
-  {
-    /* Do nothing, because the span contains the attribute itself already. */
-  }
-};
-
-template<typename StructT,
-         typename ElemT,
-         ElemT (*GetFunc)(const StructT &),
-         void (*SetFunc)(StructT &, const ElemT &)>
-class DerivedArrayWriteAttribute final : public WriteAttribute {
- private:
-  MutableSpan<StructT> data_;
-
- public:
-  DerivedArrayWriteAttribute(AttributeDomain domain, MutableSpan<StructT> data)
-      : WriteAttribute(domain, CPPType::get<ElemT>(), data.size()), data_(data)
-  {
-  }
-
-  void get_internal(const int64_t index, void *r_value) const override
-  {
-    const StructT &struct_value = data_[index];
-    const ElemT value = GetFunc(struct_value);
-    new (r_value) ElemT(value);
-  }
-
-  void set_internal(const int64_t index, const void *value) override
-  {
-    StructT &struct_value = data_[index];
-    const ElemT &typed_value = *reinterpret_cast<const ElemT *>(value);
-    SetFunc(struct_value, typed_value);
-  }
-};
+using fn::GVArrayPtr;
+using fn::GVMutableArrayPtr;
 
 /**
  * Utility to group together multiple functions that are used to access custom data on geometry
@@ -244,8 +86,8 @@ class BuiltinAttributeProvider {
   {
   }
 
-  virtual ReadAttributePtr try_get_for_read(const GeometryComponent &component) const = 0;
-  virtual WriteAttributePtr try_get_for_write(GeometryComponent &component) const = 0;
+  virtual GVArrayPtr try_get_for_read(const GeometryComponent &component) const = 0;
+  virtual GVMutableArrayPtr try_get_for_write(GeometryComponent &component) const = 0;
   virtual bool try_delete(GeometryComponent &component) const = 0;
   virtual bool try_create(GeometryComponent &UNUSED(component)) const = 0;
   virtual bool exists(const GeometryComponent &component) const = 0;
@@ -272,10 +114,10 @@ class BuiltinAttributeProvider {
  */
 class DynamicAttributesProvider {
  public:
-  virtual ReadAttributePtr try_get_for_read(const GeometryComponent &component,
-                                            const StringRef attribute_name) const = 0;
-  virtual WriteAttributePtr try_get_for_write(GeometryComponent &component,
-                                              const StringRef attribute_name) const = 0;
+  virtual ReadAttributeLookup try_get_for_read(const GeometryComponent &component,
+                                               const StringRef attribute_name) const = 0;
+  virtual WriteAttributeLookup try_get_for_write(GeometryComponent &component,
+                                                 const StringRef attribute_name) const = 0;
   virtual bool try_delete(GeometryComponent &component, const StringRef attribute_name) const = 0;
   virtual bool try_create(GeometryComponent &UNUSED(component),
                           const StringRef UNUSED(attribute_name),
@@ -309,11 +151,11 @@ class CustomDataAttributeProvider final : public DynamicAttributesProvider {
   {
   }
 
-  ReadAttributePtr try_get_for_read(const GeometryComponent &component,
-                                    const StringRef attribute_name) const final;
+  ReadAttributeLookup try_get_for_read(const GeometryComponent &component,
+                                       const StringRef attribute_name) const final;
 
-  WriteAttributePtr try_get_for_write(GeometryComponent &component,
-                                      const StringRef attribute_name) const final;
+  WriteAttributeLookup try_get_for_write(GeometryComponent &component,
+                                         const StringRef attribute_name) const final;
 
   bool try_delete(GeometryComponent &component, const StringRef attribute_name) const final;
 
@@ -332,18 +174,21 @@ class CustomDataAttributeProvider final : public DynamicAttributesProvider {
 
  private:
   template<typename T>
-  ReadAttributePtr layer_to_read_attribute(const CustomDataLayer &layer,
-                                           const int domain_size) const
+  ReadAttributeLookup layer_to_read_attribute(const CustomDataLayer &layer,
+                                              const int domain_size) const
   {
-    return std::make_unique<ArrayReadAttribute<T>>(
-        domain_, Span(static_cast<const T *>(layer.data), domain_size));
+    return {std::make_unique<fn::GVArray_For_Span<T>>(
+                Span(static_cast<const T *>(layer.data), domain_size)),
+            domain_};
   }
 
   template<typename T>
-  WriteAttributePtr layer_to_write_attribute(CustomDataLayer &layer, const int domain_size) const
+  WriteAttributeLookup layer_to_write_attribute(CustomDataLayer &layer,
+                                                const int domain_size) const
   {
-    return std::make_unique<ArrayWriteAttribute<T>>(
-        domain_, MutableSpan(static_cast<T *>(layer.data), domain_size));
+    return {std::make_unique<fn::GVMutableArray_For_MutableSpan<T>>(
+                MutableSpan(static_cast<T *>(layer.data), domain_size)),
+            domain_};
   }
 
   bool type_is_supported(CustomDataType data_type) const
@@ -357,8 +202,8 @@ class CustomDataAttributeProvider final : public DynamicAttributesProvider {
  */
 class NamedLegacyCustomDataProvider final : public DynamicAttributesProvider {
  private:
-  using AsReadAttribute = ReadAttributePtr (*)(const void *data, const int domain_size);
-  using AsWriteAttribute = WriteAttributePtr (*)(void *data, const int domain_size);
+  using AsReadAttribute = GVArrayPtr (*)(const void *data, const int domain_size);
+  using AsWriteAttribute = GVMutableArrayPtr (*)(void *data, const int domain_size);
   const AttributeDomain domain_;
   const CustomDataType attribute_type_;
   const CustomDataType stored_type_;
@@ -382,10 +227,10 @@ class NamedLegacyCustomDataProvider final : public DynamicAttributesProvider {
   {
   }
 
-  ReadAttributePtr try_get_for_read(const GeometryComponent &component,
-                                    const StringRef attribute_name) const final;
-  WriteAttributePtr try_get_for_write(GeometryComponent &component,
-                                      const StringRef attribute_name) const final;
+  ReadAttributeLookup try_get_for_read(const GeometryComponent &component,
+                                       const StringRef attribute_name) const final;
+  WriteAttributeLookup try_get_for_write(GeometryComponent &component,
+                                         const StringRef attribute_name) const final;
   bool try_delete(GeometryComponent &component, const StringRef attribute_name) const final;
   bool foreach_attribute(const GeometryComponent &component,
                          const AttributeForeachCallback callback) const final;
@@ -398,8 +243,8 @@ class NamedLegacyCustomDataProvider final : public DynamicAttributesProvider {
  * the #MVert struct, but is exposed as float3 attribute.
  */
 class BuiltinCustomDataLayerProvider final : public BuiltinAttributeProvider {
-  using AsReadAttribute = ReadAttributePtr (*)(const void *data, const int domain_size);
-  using AsWriteAttribute = WriteAttributePtr (*)(void *data, const int domain_size);
+  using AsReadAttribute = GVArrayPtr (*)(const void *data, const int domain_size);
+  using AsWriteAttribute = GVMutableArrayPtr (*)(void *data, const int domain_size);
   using UpdateOnRead = void (*)(const GeometryComponent &component);
   using UpdateOnWrite = void (*)(GeometryComponent &component);
   const CustomDataType stored_type_;
@@ -430,8 +275,8 @@ class BuiltinCustomDataLayerProvider final : public BuiltinAttributeProvider {
   {
   }
 
-  ReadAttributePtr try_get_for_read(const GeometryComponent &component) const final;
-  WriteAttributePtr try_get_for_write(GeometryComponent &component) const final;
+  GVArrayPtr try_get_for_read(const GeometryComponent &component) const final;
+  GVMutableArrayPtr try_get_for_write(GeometryComponent &component) const final;
   bool try_delete(GeometryComponent &component) const final;
   bool try_create(GeometryComponent &component) const final;
   bool exists(const GeometryComponent &component) const final;
diff --git a/source/blender/blenkernel/intern/geometry_component_mesh.cc b/source/blender/blenkernel/intern/geometry_component_mesh.cc
index 150cc4589c8..e5accd98952 100644
--- a/source/blender/blenkernel/intern/geometry_component_mesh.cc
+++ b/source/blender/blenkernel/intern/geometry_component_mesh.cc
@@ -32,7 +32,7 @@
 /* Can't include BKE_object_deform.h right now, due to an enum forward declaration.  */
 extern "C" MDeformVert *BKE_object_defgroup_data_create(ID *id);
 
-using blender::bke::ReadAttributePtr;
+using blender::fn::GVArray;
 
 /* -------------------------------------------------------------------- */
 /** \name Geometry Component Implementation
@@ -201,14 +201,14 @@ namespace blender::bke {
 
 template<typename T>
 static void adapt_mesh_domain_corner_to_point_impl(const Mesh &mesh,
-                                                   const TypedReadAttribute<T> &attribute,
+                                                   const VArray<T> &old_values,
                                                    MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
   attribute_math::DefaultMixer<T> mixer(r_values);
 
   for (const int loop_index : IndexRange(mesh.totloop)) {
-    const T value = attribute[loop_index];
+    const T value = old_values[loop_index];
     const MLoop &loop = mesh.mloop[loop_index];
     const int point_index = loop.v;
     mixer.mix_in(point_index, value);
@@ -216,43 +216,40 @@ static void adapt_mesh_domain_corner_to_point_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_corner_to_point(const Mesh &mesh,
-                                                          ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_corner_to_point(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       /* We compute all interpolated values at once, because for this interpolation, one has to
        * iterate over all loops anyway. */
       Array<T> values(mesh.totvert);
-      adapt_mesh_domain_corner_to_point_impl<T>(mesh, *attribute, values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_corner_to_point_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 static void adapt_mesh_domain_point_to_corner_impl(const Mesh &mesh,
-                                                   const TypedReadAttribute<T> &attribute,
+                                                   const VArray<T> &old_values,
                                                    MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
 
   for (const int loop_index : IndexRange(mesh.totloop)) {
     const int vertex_index = mesh.mloop[loop_index].v;
-    r_values[loop_index] = attribute[vertex_index];
+    r_values[loop_index] = old_values[vertex_index];
   }
 }
 
-static ReadAttributePtr adapt_mesh_domain_point_to_corner(const Mesh &mesh,
-                                                          ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_point_to_corner(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     /* It is not strictly necessary to compute the value for all corners here. Instead one could
@@ -260,11 +257,10 @@ static ReadAttributePtr adapt_mesh_domain_point_to_corner(const Mesh &mesh,
      * when an algorithm only accesses very few of the corner values. However, for the algorithms
      * we currently have, precomputing the array is fine. Also, it is easier to implement. */
     Array<T> values(mesh.totloop);
-    adapt_mesh_domain_point_to_corner_impl<T>(mesh, *attribute, values);
-    new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_CORNER,
-                                                                 std::move(values));
+    adapt_mesh_domain_point_to_corner_impl<T>(mesh, varray->typed<T>(), values);
+    new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
   });
-  return new_attribute;
+  return new_varray;
 }
 
 /**
@@ -274,7 +270,7 @@ static ReadAttributePtr adapt_mesh_domain_point_to_corner(const Mesh &mesh,
  */
 template<typename T>
 static void adapt_mesh_domain_corner_to_face_impl(const Mesh &mesh,
-                                                  Span<T> old_values,
+                                                  const VArray<T> &old_values,
                                                   MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totpoly);
@@ -291,26 +287,24 @@ static void adapt_mesh_domain_corner_to_face_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_corner_to_face(const Mesh &mesh,
-                                                         ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_corner_to_face(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totpoly);
-      adapt_mesh_domain_corner_to_face_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_corner_to_face_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 static void adapt_mesh_domain_corner_to_edge_impl(const Mesh &mesh,
-                                                  Span<T> old_values,
+                                                  const VArray<T> &old_values,
                                                   MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
@@ -332,26 +326,24 @@ static void adapt_mesh_domain_corner_to_edge_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_corner_to_edge(const Mesh &mesh,
-                                                         ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_corner_to_edge(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totedge);
-      adapt_mesh_domain_corner_to_edge_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_corner_to_edge_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 void adapt_mesh_domain_face_to_point_impl(const Mesh &mesh,
-                                          Span<T> old_values,
+                                          const VArray<T> &old_values,
                                           MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
@@ -370,26 +362,24 @@ void adapt_mesh_domain_face_to_point_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_face_to_point(const Mesh &mesh,
-                                                        ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_face_to_point(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totvert);
-      adapt_mesh_domain_face_to_point_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_face_to_point_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 void adapt_mesh_domain_face_to_corner_impl(const Mesh &mesh,
-                                           const Span<T> old_values,
+                                           const VArray<T> &old_values,
                                            MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
@@ -401,26 +391,24 @@ void adapt_mesh_domain_face_to_corner_impl(const Mesh &mesh,
   }
 }
 
-static ReadAttributePtr adapt_mesh_domain_face_to_corner(const Mesh &mesh,
-                                                         ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_face_to_corner(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totloop);
-      adapt_mesh_domain_face_to_corner_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_face_to_corner_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 void adapt_mesh_domain_face_to_edge_impl(const Mesh &mesh,
-                                         const Span<T> old_values,
+                                         const VArray<T> &old_values,
                                          MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
@@ -437,21 +425,19 @@ void adapt_mesh_domain_face_to_edge_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_face_to_edge(const Mesh &mesh,
-                                                       ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_face_to_edge(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totedge);
-      adapt_mesh_domain_face_to_edge_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_face_to_edge_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 /**
@@ -461,7 +447,7 @@ static ReadAttributePtr adapt_mesh_domain_face_to_edge(const Mesh &mesh,
  */
 template<typename T>
 static void adapt_mesh_domain_point_to_face_impl(const Mesh &mesh,
-                                                 const Span<T> old_values,
+                                                 const VArray<T> &old_values,
                                                  MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totpoly);
@@ -478,21 +464,19 @@ static void adapt_mesh_domain_point_to_face_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_point_to_face(const Mesh &mesh,
-                                                        ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_point_to_face(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totpoly);
-      adapt_mesh_domain_point_to_face_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_point_to_face_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 /**
@@ -502,7 +486,7 @@ static ReadAttributePtr adapt_mesh_domain_point_to_face(const Mesh &mesh,
  */
 template<typename T>
 static void adapt_mesh_domain_point_to_edge_impl(const Mesh &mesh,
-                                                 const Span<T> old_values,
+                                                 const VArray<T> &old_values,
                                                  MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totedge);
@@ -517,26 +501,24 @@ static void adapt_mesh_domain_point_to_edge_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_point_to_edge(const Mesh &mesh,
-                                                        ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_point_to_edge(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totedge);
-      adapt_mesh_domain_point_to_edge_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_point_to_edge_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 void adapt_mesh_domain_edge_to_corner_impl(const Mesh &mesh,
-                                           const Span<T> old_values,
+                                           const VArray<T> &old_values,
                                            MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totloop);
@@ -558,26 +540,24 @@ void adapt_mesh_domain_edge_to_corner_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_edge_to_corner(const Mesh &mesh,
-                                                         ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_edge_to_corner(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totloop);
-      adapt_mesh_domain_edge_to_corner_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_edge_to_corner_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 template<typename T>
 static void adapt_mesh_domain_edge_to_point_impl(const Mesh &mesh,
-                                                 const Span<T> old_values,
+                                                 const VArray<T> &old_values,
                                                  MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totvert);
@@ -593,21 +573,19 @@ static void adapt_mesh_domain_edge_to_point_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_edge_to_point(const Mesh &mesh,
-                                                        ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_edge_to_point(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totvert);
-      adapt_mesh_domain_edge_to_point_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_edge_to_point_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 /**
@@ -617,7 +595,7 @@ static ReadAttributePtr adapt_mesh_domain_edge_to_point(const Mesh &mesh,
  */
 template<typename T>
 static void adapt_mesh_domain_edge_to_face_impl(const Mesh &mesh,
-                                                const Span<T> old_values,
+                                                const VArray<T> &old_values,
                                                 MutableSpan<T> r_values)
 {
   BLI_assert(r_values.size() == mesh.totpoly);
@@ -634,87 +612,86 @@ static void adapt_mesh_domain_edge_to_face_impl(const Mesh &mesh,
   mixer.finalize();
 }
 
-static ReadAttributePtr adapt_mesh_domain_edge_to_face(const Mesh &mesh,
-                                                       ReadAttributePtr attribute)
+static GVArrayPtr adapt_mesh_domain_edge_to_face(const Mesh &mesh, GVArrayPtr varray)
 {
-  ReadAttributePtr new_attribute;
-  const CustomDataType data_type = attribute->custom_data_type();
+  GVArrayPtr new_varray;
+  const CustomDataType data_type = cpp_type_to_custom_data_type(varray->type());
   attribute_math::convert_to_static_type(data_type, [&](auto dummy) {
     using T = decltype(dummy);
     if constexpr (!std::is_void_v<attribute_math::DefaultMixer<T>>) {
       Array<T> values(mesh.totpoly);
-      adapt_mesh_domain_edge_to_face_impl<T>(mesh, attribute->get_span<T>(), values);
-      new_attribute = std::make_unique<OwnedArrayReadAttribute<T>>(ATTR_DOMAIN_POINT,
-                                                                   std::move(values));
+      adapt_mesh_domain_edge_to_face_impl<T>(mesh, varray->typed<T>(), values);
+      new_varray = std::make_unique<fn::GVArray_For_ArrayContainer<Array<T>>>(std::move(values));
     }
   });
-  return new_attribute;
+  return new_varray;
 }
 
 }  // namespace blender::bke
 
-ReadAttributePtr MeshComponent::attribute_try_adapt_domain(ReadAttributePtr attribute,
-                                                           const AttributeDomain new_domain) const
+blender::fn::GVArrayPtr MeshComponent::attribute_try_adapt_domain(
+    blender::fn::GVArrayPtr varray,
+    const AttributeDomain from_domain,
+    const AttributeDomain to_domain) const
 {
-  if (!attribute) {
+  if (!varray) {
     return {};
   }
-  if (attribute->size() == 0) {
+  if (varray->size() == 0) {
     return {};
   }
-  const AttributeDomain old_domain = attribute->domain();
-  if (old_domain == new_domain) {
-    return attribute;
+  if (from_domain == to_domain) {
+    return varray;
   }
 
-  switch (old_domain) {
+  switch (from_domain) {
     case ATTR_DOMAIN_CORNER: {
-      switch (new_domain) {
+      switch (to_domain) {
         case ATTR_DOMAIN_POINT:
-          return blender::bke::adapt_mesh_domain_corner_to_point(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_corner_to_point(*mesh_, std::move(varray));
         case ATTR_DOMAIN_FACE:
-          return blender::bke::adapt_mesh_domain_corner_to_face(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_corner_to_face(*mesh_, std::move(varray));
         case ATTR_DOMAIN_EDGE:
-          return blender::bke::adapt_mesh_domain_corner_to_edge(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_corner_to_edge(*mesh_, std::move(varray));
         default:
           break;
       }
       break;
     }
     case ATTR_DOMAIN_POINT: {
-      switch (new_domain) {
+      switch (to_domain) {
         case ATTR_DOMAIN_CORNER:
-          return blender::bke::adapt_mesh_domain_point_to_corner(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_point_to_corner(*mesh_, std::move(varray));
         case ATTR_DOMAIN_FACE:
-          return blender::bke::adapt_mesh_domain_point_to_face(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_point_to_face(*mesh_, std::move(varray));
         case ATTR_DOMAIN_EDGE:
-          return blender::bke::adapt_mesh_domain_point_to_edge(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_point_to_edge(*mesh_, std::move(varray));
         default:
           break;
       }
       break;
     }
     case ATTR_DOMAIN_FACE: {
-      switch (new_domain) {
+      switch (to_domain) {
         case ATTR_DOMAIN_POINT:
-          return blender::bke::adapt_mesh_domain_face_to_point(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_face_to_point(*mesh_, std::move(varray));
         case ATTR_DOMAIN_CORNER:
-          return blender::bke::adapt_mesh_domain_face_to_corner(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_face_to_corner(*mesh_, std::move(varray));
         case ATTR_DOMAIN_EDGE:
-          return blender::bke::adapt_mesh_domain_face_to_edge(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_face_to_edge(*mesh_, std::move(varray));
         default:
           break;
       }
       break;
     }
     case ATTR_DOMAIN_EDGE: {
-      switch (new_domain) {
+      switch (to_domain) {
         case ATTR_DOMAIN_CORNER:
-          return blender::bke::adapt_mesh_domain_edge_to_corner(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_edge_to_corner(*mesh_, std::move(varray));
         case ATTR_DOMAIN_POINT:
-          return blender::bke::adapt_mesh_domain_edge_to_point(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_edge_to_point(*mesh_, std::move(varray));
         case ATTR_DOMAIN_FACE:
-          return blender::bke::adapt_mesh_domain_edge_to_face(*mesh_, std::move(attribute));
+          return blender::bke::adapt_mesh_domain_edge_to_face(*mesh_, std::move(varray));
         default:
           break;
       }
@@ -743,25 +720,21 @@ static const Mesh *get_mesh_from_component_for_read(const GeometryComponent &com
 
 namespace blender::bke {
 
-template<typename StructT,
-         typename ElemT,
-         ElemT (*GetFunc)(const StructT &),
-         AttributeDomain Domain>
-static ReadAttributePtr make_derived_read_attribute(const void *data, const int domain_size)
+template<typename StructT, typename ElemT, ElemT (*GetFunc)(const StructT &)>
+static GVArrayPtr make_derived_read_attribute(const void *data, const int domain_size)
 {
-  return std::make_unique<DerivedArrayReadAttribute<StructT, ElemT, GetFunc>>(
-      Domain, Span<StructT>((const StructT *)data, domain_size));
+  return std::make_unique<fn::GVArray_For_DerivedSpan<StructT, ElemT, GetFunc>>(
+      Span<StructT>((const StructT *)data, domain_size));
 }
 
 template<typename StructT,
          typename ElemT,
          ElemT (*GetFunc)(const StructT &),
-         void (*SetFunc)(StructT &, const ElemT &),
-         AttributeDomain Domain>
-static WriteAttributePtr make_derived_write_attribute(void *data, const int domain_size)
+         void (*SetFunc)(StructT &, ElemT)>
+static GVMutableArrayPtr make_derived_write_attribute(void *data, const int domain_size)
 {
-  return std::make_unique<DerivedArrayWriteAttribute<StructT, ElemT, GetFunc, SetFunc>>(
-      Domain, MutableSpan<StructT>((StructT *)data, domain_size));
+  return std::make_unique<fn::GVMutableArray_For_DerivedSpan<StructT, ElemT, GetFunc, SetFunc>>(
+      MutableSpan<StructT>((StructT *)data, domain_size));
 }
 
 static float3 get_vertex_position(const MVert &vert)
@@ -769,7 +742,7 @@ static float3 get_vertex_position(const MVert &vert)
   return float3(vert.co);
 }
 
-static void set_vertex_position(MVert &vert, const float3 &position)
+static void set_vertex_position(MVert &vert, float3 position)
 {
   copy_v3_v3(vert.co, position);
 }
@@ -787,7 +760,7 @@ static int get_material_index(const MPoly &mpoly)
   return static_cast<int>(mpoly.mat_nr);
 }
 
-static void set_material_index(MPoly &mpoly, const int &index)
+static void set_material_index(MPoly &mpoly, int index)
 {
   mpoly.mat_nr = static_cast<short>(std::clamp(index, 0, SHRT_MAX));
 }
@@ -797,7 +770,7 @@ static bool get_shade_smooth(const MPoly &mpoly)
   return mpoly.flag & ME_SMOOTH;
 }
 
-static void set_shade_smooth(MPoly &mpoly, const bool &value)
+static void set_shade_smooth(MPoly &mpoly, bool value)
 {
   SET_FLAG_FROM_TEST(mpoly.flag, value, ME_SMOOTH);
 }
@@ -807,7 +780,7 @@ static float2 get_loop_uv(const MLoopUV &uv)
   return float2(uv.uv);
 }
 
-static void set_loop_uv(MLoopUV &uv, const float2 &co)
+static void set_loop_uv(MLoopUV &uv, float2 co)
 {
   copy_v2_v2(uv.uv, co);
 }
@@ -821,7 +794,7 @@ static Color4f get_loop_color(const MLoopCol &col)
   return linear_color;
 }
 
-static void set_loop_color(MLoopCol &col, const Color4f &linear_color)
+static void set_loop_color(MLoopCol &col, Color4f linear_color)
 {
   linearrgb_to_srgb_uchar4(&col.r, linear_color);
 }
@@ -831,71 +804,62 @@ static float get_crease(const MEdge &edge)
   return edge.crease / 255.0f;
 }
 
-static void set_crease(MEdge &edge, const float &value)
+static void set_crease(MEdge &edge, float value)
 {
   edge.crease = round_fl_to_uchar_clamp(value * 255.0f);
 }
 
-class VertexWeightWriteAttribute final : public WriteAttribute {
+class VMutableArray_For_VertexWeights final : public VMutableArray<float> {
  private:
   MDeformVert *dverts_;
   const int dvert_index_;
 
  public:
-  VertexWeightWriteAttribute(MDeformVert *dverts, const int totvert, const int dvert_index)
-      : WriteAttribute(ATTR_DOMAIN_POINT, CPPType::get<float>(), totvert),
-        dverts_(dverts),
-        dvert_index_(dvert_index)
+  VMutableArray_For_VertexWeights(MDeformVert *dverts, const int totvert, const int dvert_index)
+      : VMutableArray<float>(totvert), dverts_(dverts), dvert_index_(dvert_index)
   {
   }
 
-  void get_internal(const int64_t index, void *r_value) const override
+  float get_impl(const int64_t index) const override
   {
-    get_internal(dverts_, dvert_index_, index, r_value);
+    return get_internal(dverts_, dvert_index_, index);
   }
 
-  void set_internal(const int64_t index, const void *value) override
+  void set_impl(const int64_t index, const float value) override
   {
     MDeformWeight *weight = BKE_defvert_ensure_index(&dverts_[index], dvert_index_);
-    weight->weight = *reinterpret_cast<const float *>(value);
+    weight->weight = value;
   }
 
-  static void get_internal(const MDeformVert *dverts,
-                           const int dvert_index,
-                           const int64_t index,
-                           void *r_value)
+  static float get_internal(const MDeformVert *dverts, const int dvert_index, const int64_t index)
   {
     if (dverts == nullptr) {
-      *(float *)r_value = 0.0f;
-      return;
+      return 0.0f;
     }
     const MDeformVert &dvert = dverts[index];
     for (const MDeformWeight &weight : Span(dvert.dw, dvert.totweight)) {
       if (weight.def_nr == dvert_index) {
-        *(float *)r_value = weight.weight;
-        return;
+        return weight.weight;
       }
     }
-    *(float *)r_value = 0.0f;
+    return 0.0f;
   }
 };
 
-class VertexWeightReadAttribute final : public ReadAttribute {
+class VArray_For_VertexWeights final : public VArray<float> {
  private:
   const MDeformVert *dverts_;
   const int dvert_index_;
 
  public:
-  VertexWeightReadAttribute(const MDeformVert *dverts, const int totvert, const int dvert_index)
-      : ReadAttribute(ATTR_DOMAIN_POINT, CPPType::get<float>(), totvert),
-        dverts_(dverts),
-        dvert_index_(dvert_index)
+  VArray_For_VertexWeights(const MDeformVert *dverts, const int totvert, const int dvert_index)
+      : VArray<float>(totvert), dverts_(dverts), dvert_index_(dvert_index)
   {
   }
 
-  void get_internal(const int64_t index, void *r_value) const override
+  float get_impl(const int64_t index) const override
   {
-    VertexWeightWriteAttribute::get_internal(dverts_, dvert_index_, index, r_value);
+    return VMutableArray_For_VertexWeights::get_internal(dverts_, dvert_index_, index);
   }
 };
 
@@ -904,8 +868,8 @@ class VertexWeightReadAttribute final : public ReadAttribute {
  */
 class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
  public:
-  ReadAttributePtr try_get_for_read(const GeometryComponent &component,
-                                    const StringRef attribute_name) const final
+  ReadAttributeLookup try_get_for_read(const GeometryComponent &component,
+                                       const StringRef attribute_name) const final
   {
     BLI_assert(component.type() == GEO_COMPONENT_TYPE_MESH);
     const MeshComponent &mesh_component = static_cast<const MeshComponent &>(component);
@@ -917,15 +881,17 @@ class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
     }
     if (mesh == nullptr || mesh->dvert == nullptr) {
       static const float default_value = 0.0f;
-      return std::make_unique<ConstantReadAttribute>(
-          ATTR_DOMAIN_POINT, mesh->totvert, CPPType::get<float>(), &default_value);
+      return {std::make_unique<fn::GVArray_For_SingleValueRef>(
+                  CPPType::get<float>(), mesh->totvert, &default_value),
+              ATTR_DOMAIN_POINT};
     }
-    return std::make_unique<VertexWeightReadAttribute>(
-        mesh->dvert, mesh->totvert, vertex_group_index);
+    return {std::make_unique<fn::GVArray_For_EmbeddedVArray<float, VArray_For_VertexWeights>>(
+                mesh->totvert, mesh->dvert, mesh->totvert, vertex_group_index),
+            ATTR_DOMAIN_POINT};
   }
 
-  WriteAttributePtr try_get_for_write(GeometryComponent &component,
-                                      const StringRef attribute_name) const final
+  WriteAttributeLookup try_get_for_write(GeometryComponent &component,
+                                         const StringRef attribute_name) const final
   {
     BLI_assert(component.type() == GEO_COMPONENT_TYPE_MESH);
     MeshComponent &mesh_component = static_cast<MeshComponent &>(component);
@@ -946,8 +912,11 @@ class VertexGroupsAttributeProvider final : public DynamicAttributesProvider {
       mesh->dvert = (MDeformVert *)CustomData_duplicate_referenced_layer(
           &mesh->vdata, CD_MDEFORMVERT, mesh->totvert);
     }
-    return std::make_unique<blender::bke::VertexWeightWriteAttribute>(
-        mesh->dvert, mesh->totvert, vertex_group_index);
+    return {
+        std::make_unique<
+            fn::GVMutableArray_For_EmbeddedVMutableArray<float, VMutableArray_For_VertexWeights>>(
+            mesh->totvert, mesh->dvert, mesh->totvert, vertex_group_index),
+        ATTR_DOMAIN_POINT};
   }
 
   bool try_delete(GeometryComponent &component, const StringRef attribute_name) const final
@@ -1009,7 +978,7 @@ class NormalAttributeProvider final : public BuiltinAttributeProvider {
   {
   }
 
-  ReadAttributePtr try_get_for_read(const GeometryComponent &component) const final
+  GVArrayPtr try_get_for_read(const GeometryComponent &component) const final
   {
     const MeshComponent &mesh_component = static_cast<const MeshComponent &>(component);
     const Mesh *mesh = mesh_component.get_for_read();
@@ -1022,8 +991,8 @@ class NormalAttributeProvider final : public BuiltinAttributeProvider {
         CustomData_has_layer(&mesh->pdata, CD_NORMAL)) {
       const void *data = CustomData_get_layer(&mesh->pdata, CD_NORMAL);
 
-      return std::make_unique<ArrayReadAttribute<float3>>(
-          ATTR_DOMAIN_FACE, Span<float3>((const float3 *)data, mesh->totpoly));
+      return std::make_unique<fn::GVArray_For_Span<float3>>(
+          Span<float3>((const float3 *)data, mesh->totpoly));
     }
 
     Array<float3> normals(mesh->totpoly);
@@ -1032,10 +1001,10 @@ class NormalAttributeProvider final : public BuiltinAttributeProvider {
       BKE_mesh_calc_poly_normal(poly, &mesh->mloop[poly->loopstart], mesh->mvert, normals[i]);
     }
 
-    return std::make_unique<OwnedArrayReadAttribute<float3>>(ATTR_DOMAIN_FACE, std::move(normals));
+    return std::make_unique<fn::GVArray_For_ArrayContainer<Array<float3>>>(std::move(normals));
   }
 
-  WriteAttributePtr try_get_for_write(GeometryComponent &UNUSED(component)) const final
+  GVMutableArrayPtr try_get_for_write(GeometryComponent &UNUSED(component)) const final
   {
     return {};
   }
@@ -1105,12 +1074,8 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       BuiltinAttributeProvider::Writable,
       BuiltinAttributeProvider::NonDeletable,
       point_access,
-      make_derived_read_attribute<MVert, float3, get_vertex_position, ATTR_DOMAIN_POINT>,
-      make_derived_write_attribute<MVert,
-                                   float3,
-                                   get_vertex_position,
-                                   set_vertex_position,
-                                   ATTR_DOMAIN_POINT>,
+      make_derived_read_attribute<MVert, float3, get_vertex_position>,
+      make_derived_write_attribute<MVert, float3, get_vertex_position, set_vertex_position>,
       tag_normals_dirty_when_writing_position);
 
   static NormalAttributeProvider normal;
@@ -1124,12 +1089,8 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       BuiltinAttributeProvider::Writable,
       BuiltinAttributeProvider::NonDeletable,
       face_access,
-      make_derived_read_attribute<MPoly, int, get_material_index, ATTR_DOMAIN_FACE>,
-      make_derived_write_attribute<MPoly,
-                                   int,
-                                   get_material_index,
-                                   set_material_index,
-                                   ATTR_DOMAIN_FACE>,
+      make_derived_read_attribute<MPoly, int, get_material_index>,
+      make_derived_write_attribute<MPoly, int, get_material_index, set_material_index>,
       nullptr);
 
   static BuiltinCustomDataLayerProvider shade_smooth(
@@ -1141,12 +1102,8 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       BuiltinAttributeProvider::Writable,
       BuiltinAttributeProvider::NonDeletable,
       face_access,
-      make_derived_read_attribute<MPoly, bool, get_shade_smooth, ATTR_DOMAIN_FACE>,
-      make_derived_write_attribute<MPoly,
-                                   bool,
-                                   get_shade_smooth,
-                                   set_shade_smooth,
-                                   ATTR_DOMAIN_FACE>,
+      make_derived_read_attribute<MPoly, bool, get_shade_smooth>,
+      make_derived_write_attribute<MPoly, bool, get_shade_smooth, set_shade_smooth>,
       nullptr);
 
   static BuiltinCustomDataLayerProvider crease(
@@ -1158,8 +1115,8 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       BuiltinAttributeProvider::Writable,
       BuiltinAttributeProvider::NonDeletable,
       edge_access,
-      make_derived_read_attribute<MEdge, float, get_crease, ATTR_DOMAIN_EDGE>,
-      make_derived_write_attribute<MEdge, float, get_crease, set_crease, ATTR_DOMAIN_EDGE>,
+      make_derived_read_attribute<MEdge, float, get_crease>,
+      make_derived_write_attribute<MEdge, float, get_crease, set_crease>,
       nullptr);
 
   static NamedLegacyCustomDataProvider uvs(
@@ -1167,20 +1124,16 @@ static ComponentAttributeProviders create_attribute_providers_for_mesh()
       CD_PROP_FLOAT2,
       CD_MLOOPUV,
       corner_access,
-      make_derived_read_attribute<MLoopUV, float2, get_loop_uv, ATTR_DOMAIN_CORNER>,
-      make_derived_write_attribute<MLoopUV, float2, get_loop_uv, set_loop_uv, ATTR_DOMAIN_CORNER>);
+      make_derived_read_attribute<MLoopUV, float2, get_loop_uv>,
+      make_derived_write_attribute<MLoopUV, float2, get_loop_uv, set_loop_uv>);
 
   static NamedLegacyCustomDataProvider vertex_colors(
       ATTR_DOMAIN_CORNER,
       CD_PROP_COLOR,
       CD_MLOOPCOL,
       corner_access,
-      make_derived_read_attribute<MLoopCol, Color4f, get_loop_color, ATTR_DOMAIN_CORNER>,
-      make_derived_write_attribute<MLoopCol,
-                                   Color4f,
-                                   get_loop_color,
-                                   set_loop_color,
-                                   ATTR_DOMAIN_CORNER>);
+      make_derived_read_attribute<MLoopCol, Color4f, get_loop_color>,
+      make_derived_write_attribute<MLoopCol, Color4f, get_loop_color, set_loop_color>);
 
   static VertexGroupsAttributeProvider vertex_groups;
   static CustomDataAttributeProvider corner_custom_data(ATTR_DOMAIN_CORNER, corner_access);
diff --git a/source/blender/blenkernel/intern/geometry_component_pointcloud.cc b/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
index 135de14b4f7..6c4af7a6d23 100644
--- a/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
+++ b/source/blender/blenkernel/intern/geometry_component_pointcloud.cc
@@ -140,16 +140,17 @@ int PointCloudComponent::attribute_domain_size(const AttributeDomain domain) con
 
 namespace blender::bke {
 
-template<typename T, AttributeDomain Domain>
-static ReadAttributePtr make_array_read_attribute(const void *data, const int domain_size)
+template<typename T>
+static GVArrayPtr make_array_read_attribute(const void *data, const int domain_size)
 {
-  return std::make_unique<ArrayReadAttribute<T>>(Domain, Span<T>((const T *)data, domain_size));
+  return std::make_unique<fn::GVArray_For_Span<T>>(Span<T>((const T *)data, domain_size));
 }
 
-template<typename T, AttributeDomain Domain>
-static WriteAttributePtr make_array_write_attribute(void *data, const int domain_size)
+template<typename T>
+static GVMutableArrayPtr make_array_write_attribute(void *data, const int domain_size)
 {
-  return std::make_unique<ArrayWriteAttribute<T>>(Domain, MutableSpan<T>((T *)data, domain_size));
+  return std::make_unique<fn::GVMutableArray_For_MutableSpan<T>>(
+      MutableSpan<T>((T *)data, domain_size));
 }
 
 /**
@@ -179,30 +180,28 @@ static ComponentAttributeProviders create_attribute_providers_for_point_cloud()
       },
       update_custom_data_pointers};
 
-  static BuiltinCustomDataLayerProvider position(
-      "position",
-      ATTR_DOMAIN_POINT,
-      CD_PROP_FLOAT3,
-      CD_PROP_FLOAT3,
-      BuiltinAttributeProvider::NonCreatable,
-      BuiltinAttributeProvider::Writable,
-      BuiltinAttributeProvider::NonDeletable,
-      point_access,
-      make_array_read_attribute<float3, ATTR_DOMAIN_POINT>,
-      make_array_write_attribute<float3, ATTR_DOMAIN_POINT>,
-      nullptr);
-  static BuiltinCustomDataLayerProvider radius(
-      "radius",
-      ATTR_DOMAIN_POINT,
-      CD_PROP_FLOAT,
-      CD_PROP_FLOAT,
-      BuiltinAttributeProvider::Creatable,
-      BuiltinAttributeProvider::Writable,
-      BuiltinAttributeProvider::Deletable,
-      point_access,
-      make_array_read_attribute<float, ATTR_DOMAIN_POINT>,
-      make_array_write_attribute<float, ATTR_DOMAIN_POINT>,
-      nullptr);
+  static BuiltinCustomDataLayerProvider position("position",
+                                                 ATTR_DOMAIN_POINT,
+                                                 CD_PROP_FLOAT3,
+                                                 CD_PROP_FLOAT3,
+                                                 BuiltinAttributeProvider::NonCreatable,
+                                                 BuiltinAttributeProvider::Writable,
+                                                 BuiltinAttributeProvider::NonDeletable,
+                                                 point_access,
+                                                 make_array_read_attribute<float3>,
+                                                 make_array_write_attribute<float3>,
+                                                 nullptr);
+  static BuiltinCustomDataLayerProvider radius("radius",
+                                               ATTR_DOMAIN_POINT,
+                                               CD_PROP_FLOAT,
+                                               CD_PROP_FLOAT,
+                                               BuiltinAttributeProvider::Creatable,
+                                               BuiltinAttributeProvider::Writable,
+                                               BuiltinAttributeProvider::Deletable,
+                                               point_access,
+                                               make_array_read_attribute<float>,
+                                               make_array_write_attribute<float>,
+                                               nullptr);
   static CustomDataAttributeProvider point_custom_data(ATTR_DOMAIN_POINT, point_access);
   return ComponentAttributeProviders({&position, &radius}, {&point_custom_data});
 }
diff --git a/source/blender/blenkernel/intern/geometry_set_instances.cc b/source/blender/blenkernel/intern/geometry_set_instances.cc
index 07d0e520c93..2e9f6daabad 100644
--- a/source/blender/blenkernel/intern/geometry_set_instances.cc
+++ b/source/blender/blenkernel/intern/geometry_set_instances.cc
@@ -450,12 +450,13 @@ static void join_attributes(Span<GeometryInstanceGroup> set_groups,
     BLI_assert(cpp_type != nullptr);
 
     result.attribute_try_create(entry.key, domain_output, data_type_output);
-    WriteAttributePtr write_attribute = result.attribute_try_get_for_write(name);
-    if (!write_attribute || &write_attribute->cpp_type() != cpp_type ||
-        write_attribute->domain() != domain_output) {
+    WriteAttributeLookup write_attribute = result.attribute_try_get_for_write(name);
+    if (!write_attribute || &write_attribute.varray->type() != cpp_type ||
+        write_attribute.domain != domain_output) {
       continue;
     }
-    fn::GMutableSpan dst_span = write_attribute->get_span_for_write_only();
+
+    fn::GVMutableArray_GSpan dst_span{*write_attribute.varray};
 
     int offset = 0;
     for (const GeometryInstanceGroup &set_group : set_groups) {
@@ -467,11 +468,11 @@ static void join_attributes(Span<GeometryInstanceGroup> set_groups,
           if (domain_size == 0) {
             continue; /* Domain size is 0, so no need to increment the offset. */
           }
-          ReadAttributePtr source_attribute = component.attribute_try_get_for_read(
+          GVArrayPtr source_attribute = component.attribute_try_get_for_read(
               name, domain_output, data_type_output);
 
           if (source_attribute) {
-            fn::GSpan src_span = source_attribute->get_span();
+            fn::GVArray_GSpan src_span{*source_attribute};
             const void *src_buffer = src_span.data();
             for (const int UNUSED(i) : set_group.transforms.index_range()) {
               void *dst_buffer = dst_span[offset];
@@ -486,7 +487,7 @@ static void join_attributes(Span<GeometryInstanceGroup> set_groups,
       }
     }
 
-    write_attribute->apply_span();
+    dst_span.save();
   }
 }