Fix of loading the variable layer height profile and the SLA support

points for projects with instances.

3mf does not support a concept of instances, therefore all the instances
of all objects are indexed in a linear fashion. However, the 3mf files
index the layer height profiles and the SLA support points with
the object ID. The loading was fixed to take the different indexing
into account.

1 files changed, 73 insertions, 42 deletions

diff --git a/src/libslic3r/Format/3mf.cpp b/src/libslic3r/Format/3mf.cpp
index 5a16a6e8f..4d59e5664 100644
--- a/src/libslic3r/Format/3mf.cpp
+++ b/src/libslic3r/Format/3mf.cpp
@@ -247,7 +247,10 @@ namespace Slic3r {
 
         struct CurrentObject
         {
+            // ID of the object inside the 3MF file, 1 based.
             int id;
+            // Index of the ModelObject in its respective Model, zero based.
+            int model_object_idx;
             Geometry geometry;
             ModelObject* object;
             ComponentsList components;
@@ -260,6 +263,7 @@ namespace Slic3r {
             void reset()
             {
                 id = -1;
+                model_object_idx = -1;
                 geometry.reset();
                 object = nullptr;
                 components.clear();
@@ -319,7 +323,8 @@ namespace Slic3r {
             VolumeMetadataList volumes;
         };
 
-        typedef std::map<int, ModelObject*> IdToModelObjectMap;
+        // Map from a 1 based 3MF object ID to a 0 based ModelObject index inside m_model->objects.
+        typedef std::map<int, int> IdToModelObjectMap;
         typedef std::map<int, ComponentsList> IdToAliasesMap;
         typedef std::vector<Instance> InstancesList;
         typedef std::map<int, ObjectMetadata> IdToMetadataMap;
@@ -572,6 +577,7 @@ namespace Slic3r {
 
         for (const IdToModelObjectMap::value_type& object : m_objects)
         {
+            ModelObject *model_object = m_model->objects[object.second];
             ObjectMetadata::VolumeMetadataList volumes;
             ObjectMetadata::VolumeMetadataList* volumes_ptr = nullptr;
 
@@ -582,14 +588,16 @@ namespace Slic3r {
                 return false;
             }
 
-            IdToLayerHeightsProfileMap::iterator obj_layer_heights_profile = m_layer_heights_profiles.find(object.first);
+            // m_layer_heights_profiles are indexed by a 1 based model object index.
+            IdToLayerHeightsProfileMap::iterator obj_layer_heights_profile = m_layer_heights_profiles.find(object.second + 1);
             if (obj_layer_heights_profile != m_layer_heights_profiles.end())
-                object.second->layer_height_profile = obj_layer_heights_profile->second;
+                model_object->layer_height_profile = obj_layer_heights_profile->second;
 
-            IdToSlaSupportPointsMap::iterator obj_sla_support_points = m_sla_support_points.find(object.first);
+            // m_sla_support_points are indexed by a 1 based model object index.
+            IdToSlaSupportPointsMap::iterator obj_sla_support_points = m_sla_support_points.find(object.second + 1);
             if (obj_sla_support_points != m_sla_support_points.end() && !obj_sla_support_points->second.empty()) {
-                object.second->sla_support_points = obj_sla_support_points->second;
-                object.second->sla_points_status = sla::PointsStatus::UserModified;
+                model_object->sla_support_points = obj_sla_support_points->second;
+                model_object->sla_points_status = sla::PointsStatus::UserModified;
             }
 
             IdToMetadataMap::iterator obj_metadata = m_objects_metadata.find(object.first);
@@ -601,9 +609,9 @@ namespace Slic3r {
                 for (const Metadata& metadata : obj_metadata->second.metadata)
                 {
                     if (metadata.key == "name")
-                        object.second->name = metadata.value;
+                        model_object->name = metadata.value;
                     else
-                        object.second->config.set_deserialize(metadata.key, metadata.value);
+                        model_object->config.set_deserialize(metadata.key, metadata.value);
                 }
 
                 // select object's detected volumes
@@ -620,7 +628,7 @@ namespace Slic3r {
                 volumes_ptr = &volumes;
             }
 
-            if (!_generate_volumes(*object.second, obj_geometry->second, *volumes_ptr))
+            if (!_generate_volumes(*model_object, obj_geometry->second, *volumes_ptr))
                 return false;
         }
 
@@ -828,19 +836,20 @@ namespace Slic3r {
 
                 if (version == 0) {
                     for (unsigned int i=0; i<object_data_points.size(); i+=3)
-                    sla_support_points.emplace_back(std::atof(object_data_points[i+0].c_str()),
-                                                    std::atof(object_data_points[i+1].c_str()),
-                                                    std::atof(object_data_points[i+2].c_str()),
+                    sla_support_points.emplace_back(float(std::atof(object_data_points[i+0].c_str())),
+                                                    float(std::atof(object_data_points[i+1].c_str())),
+													float(std::atof(object_data_points[i+2].c_str())),
                                                     0.4f,
                                                     false);
                 }
                 if (version == 1) {
                     for (unsigned int i=0; i<object_data_points.size(); i+=5)
-                    sla_support_points.emplace_back(std::atof(object_data_points[i+0].c_str()),
-                                                    std::atof(object_data_points[i+1].c_str()),
-                                                    std::atof(object_data_points[i+2].c_str()),
-                                                    std::atof(object_data_points[i+3].c_str()),
-                                                    std::atof(object_data_points[i+4].c_str()));
+                    sla_support_points.emplace_back(float(std::atof(object_data_points[i+0].c_str())),
+                                                    float(std::atof(object_data_points[i+1].c_str())),
+                                                    float(std::atof(object_data_points[i+2].c_str())),
+                                                    float(std::atof(object_data_points[i+3].c_str())),
+													//FIXME storing boolean as 0 / 1 and importing it as float.
+                                                    std::abs(std::atof(object_data_points[i+4].c_str()) - 1.) < EPSILON);
                 }
 
                 if (!sla_support_points.empty())
@@ -1029,8 +1038,9 @@ namespace Slic3r {
         // deletes all non-built or non-instanced objects
         for (const IdToModelObjectMap::value_type& object : m_objects)
         {
-            if ((object.second != nullptr) && (object.second->instances.size() == 0))
-                m_model->delete_object(object.second);
+            ModelObject *model_object = m_model->objects[object.second];
+            if ((model_object != nullptr) && (model_object->instances.size() == 0))
+                m_model->delete_object(model_object);
         }
 
         // applies instances' matrices
@@ -1070,6 +1080,7 @@ namespace Slic3r {
         if (is_valid_object_type(get_attribute_value_string(attributes, num_attributes, TYPE_ATTR)))
         {
             // create new object (it may be removed later if no instances are generated from it)
+            m_curr_object.model_object_idx = (int)m_model->objects.size();
             m_curr_object.object = m_model->add_object();
             if (m_curr_object.object == nullptr)
             {
@@ -1121,7 +1132,7 @@ namespace Slic3r {
                 // stores the object for later use
                 if (m_objects.find(m_curr_object.id) == m_objects.end())
                 {
-                    m_objects.insert(IdToModelObjectMap::value_type(m_curr_object.id, m_curr_object.object));
+                    m_objects.insert(IdToModelObjectMap::value_type(m_curr_object.id, m_curr_object.model_object_idx));
                     m_objects_aliases.insert(IdToAliasesMap::value_type(m_curr_object.id, ComponentsList(1, Component(m_curr_object.id)))); // aliases itself
                 }
                 else
@@ -1328,14 +1339,14 @@ namespace Slic3r {
             // aliasing to itself
 
             IdToModelObjectMap::iterator object_item = m_objects.find(object_id);
-            if ((object_item == m_objects.end()) || (object_item->second == nullptr))
+            if ((object_item == m_objects.end()) || (object_item->second == -1))
             {
                 add_error("Found invalid object");
                 return false;
             }
             else
             {
-                ModelInstance* instance = object_item->second->add_instance();
+                ModelInstance* instance = m_model->objects[object_item->second]->add_instance();
                 if (instance == nullptr)
                 {
                     add_error("Unable to add object instance");
@@ -1600,8 +1611,6 @@ namespace Slic3r {
         typedef std::vector<BuildItem> BuildItemsList;
         typedef std::map<int, ObjectData> IdToObjectDataMap;
 
-        IdToObjectDataMap m_objects_data;
-
     public:
         bool save_model_to_file(const std::string& filename, Model& model, const DynamicPrintConfig* config);
 
@@ -1609,14 +1618,14 @@ namespace Slic3r {
         bool _save_model_to_file(const std::string& filename, Model& model, const DynamicPrintConfig* config);
         bool _add_content_types_file_to_archive(mz_zip_archive& archive);
         bool _add_relationships_file_to_archive(mz_zip_archive& archive);
-        bool _add_model_file_to_archive(mz_zip_archive& archive, Model& model);
+        bool _add_model_file_to_archive(mz_zip_archive& archive, const Model& model, IdToObjectDataMap &objects_data);
         bool _add_object_to_model_stream(std::stringstream& stream, unsigned int& object_id, ModelObject& object, BuildItemsList& build_items, VolumeToOffsetsMap& volumes_offsets);
         bool _add_mesh_to_object_stream(std::stringstream& stream, ModelObject& object, VolumeToOffsetsMap& volumes_offsets);
         bool _add_build_to_model_stream(std::stringstream& stream, const BuildItemsList& build_items);
         bool _add_layer_height_profile_file_to_archive(mz_zip_archive& archive, Model& model);
         bool _add_sla_support_points_file_to_archive(mz_zip_archive& archive, Model& model);
         bool _add_print_config_file_to_archive(mz_zip_archive& archive, const DynamicPrintConfig &config);
-        bool _add_model_config_file_to_archive(mz_zip_archive& archive, const Model& model);
+        bool _add_model_config_file_to_archive(mz_zip_archive& archive, const Model& model, const IdToObjectDataMap &objects_data);
     };
 
     bool _3MF_Exporter::save_model_to_file(const std::string& filename, Model& model, const DynamicPrintConfig* config)
@@ -1630,8 +1639,6 @@ namespace Slic3r {
         mz_zip_archive archive;
         mz_zip_zero_struct(&archive);
 
-        m_objects_data.clear();
-
         mz_bool res = mz_zip_writer_init_file(&archive, filename.c_str(), 0);
         if (res == 0)
         {
@@ -1639,7 +1646,8 @@ namespace Slic3r {
             return false;
         }
 
-        // adds content types file
+        // Adds content types file ("[Content_Types].xml";).
+        // The content of this file is the same for each PrusaSlicer 3mf.
         if (!_add_content_types_file_to_archive(archive))
         {
             mz_zip_writer_end(&archive);
@@ -1647,7 +1655,9 @@ namespace Slic3r {
             return false;
         }
 
-        // adds relationships file
+        // Adds relationships file ("_rels/.rels"). 
+        // The content of this file is the same for each PrusaSlicer 3mf.
+        // The relationshis file contains a reference to the geometry file "3D/3dmodel.model", the name was chosen to be compatible with CURA.
         if (!_add_relationships_file_to_archive(archive))
         {
             mz_zip_writer_end(&archive);
@@ -1655,15 +1665,19 @@ namespace Slic3r {
             return false;
         }
 
-        // adds model file
-        if (!_add_model_file_to_archive(archive, model))
+        // Adds model file ("3D/3dmodel.model").
+        // This is the one and only file that contains all the geometry (vertices and triangles) of all ModelVolumes.
+        IdToObjectDataMap objects_data;
+        if (!_add_model_file_to_archive(archive, model, objects_data))
         {
             mz_zip_writer_end(&archive);
             boost::filesystem::remove(filename);
             return false;
         }
 
-        // adds layer height profile file
+        // Adds layer height profile file ("Metadata/Slic3r_PE_layer_heights_profile.txt").
+        // All layer height profiles of all ModelObjects are stored here, indexed by 1 based index of the ModelObject in Model.
+        // The index differes from the index of an object ID of an object instance of a 3MF file!
         if (!_add_layer_height_profile_file_to_archive(archive, model))
         {
             mz_zip_writer_end(&archive);
@@ -1671,7 +1685,9 @@ namespace Slic3r {
             return false;
         }
 
-        // adds sla support points file
+        // Adds sla support points file ("Metadata/Slic3r_PE_sla_support_points.txt").
+        // All  sla support points of all ModelObjects are stored here, indexed by 1 based index of the ModelObject in Model.
+        // The index differes from the index of an object ID of an object instance of a 3MF file!
         if (!_add_sla_support_points_file_to_archive(archive, model))
         {
             mz_zip_writer_end(&archive);
@@ -1679,7 +1695,8 @@ namespace Slic3r {
             return false;
         }
 
-        // adds slic3r print config file
+        // Adds slic3r print config file ("Metadata/Slic3r_PE.config").
+        // This file contains the content of FullPrintConfing / SLAFullPrintConfig.
         if (config != nullptr)
         {
             if (!_add_print_config_file_to_archive(archive, *config))
@@ -1690,8 +1707,11 @@ namespace Slic3r {
             }
         }
 
-        // adds slic3r model config file
-        if (!_add_model_config_file_to_archive(archive, model))
+        // Adds slic3r model config file ("Metadata/Slic3r_PE_model.config").
+        // This file contains all the attributes of all ModelObjects and their ModelVolumes (names, parameter overrides).
+        // As there is just a single Indexed Triangle Set data stored per ModelObject, offsets of volumes into their respective Indexed Triangle Set data
+        // is stored here as well.
+        if (!_add_model_config_file_to_archive(archive, model, objects_data))
         {
             mz_zip_writer_end(&archive);
             boost::filesystem::remove(filename);
@@ -1750,7 +1770,7 @@ namespace Slic3r {
         return true;
     }
 
-    bool _3MF_Exporter::_add_model_file_to_archive(mz_zip_archive& archive, Model& model)
+	bool _3MF_Exporter::_add_model_file_to_archive(mz_zip_archive& archive, const Model& model, IdToObjectDataMap &objects_data)
     {
         std::stringstream stream;
         // https://en.cppreference.com/w/cpp/types/numeric_limits/max_digits10
@@ -1763,17 +1783,24 @@ namespace Slic3r {
         stream << " <" << METADATA_TAG << " name=\"" << SLIC3RPE_3MF_VERSION << "\">" << VERSION_3MF << "</" << METADATA_TAG << ">\n";
         stream << " <" << RESOURCES_TAG << ">\n";
 
+        // Instance transformations, indexed by the 3MF object ID (which is a linear serialization of all instances of all ModelObjects).
         BuildItemsList build_items;
 
+        // The object_id here is a one based identifier of the first instance of a ModelObject in the 3MF file, where
+        // all the object instances of all ModelObjects are stored and indexed in a 1 based linear fashion.
+        // Therefore the list of object_ids here may not be continuous.
         unsigned int object_id = 1;
         for (ModelObject* obj : model.objects)
         {
             if (obj == nullptr)
                 continue;
 
+            // Index of an object in the 3MF file corresponding to the 1st instance of a ModelObject.
             unsigned int curr_id = object_id;
-            IdToObjectDataMap::iterator object_it = m_objects_data.insert(IdToObjectDataMap::value_type(curr_id, ObjectData(obj))).first;
-
+            IdToObjectDataMap::iterator object_it = objects_data.insert(IdToObjectDataMap::value_type(curr_id, ObjectData(obj))).first;
+            // Store geometry of all ModelVolumes contained in a single ModelObject into a single 3MF indexed triangle set object.
+            // object_it->second.volumes_offsets will contain the offsets of the ModelVolumes in that single indexed triangle set.
+            // object_id will be increased to point to the 1st instance of the next ModelObject.
             if (!_add_object_to_model_stream(stream, object_id, *obj, build_items, object_it->second.volumes_offsets))
             {
                 add_error("Unable to add object to archive");
@@ -1783,6 +1810,7 @@ namespace Slic3r {
 
         stream << " </" << RESOURCES_TAG << ">\n";
 
+        // Store the transformations of all the ModelInstances of all ModelObjects, indexed in a linear fashion.
         if (!_add_build_to_model_stream(stream, build_items))
         {
             add_error("Unable to add build to archive");
@@ -1807,6 +1835,7 @@ namespace Slic3r {
         unsigned int id = 0;
         for (const ModelInstance* instance : object.instances)
         {
+			assert(instance != nullptr);
             if (instance == nullptr)
                 continue;
 
@@ -1829,6 +1858,8 @@ namespace Slic3r {
             }
 
             Transform3d t = instance->get_matrix();
+            // instance_id is just a 1 indexed index in build_items.
+            assert(instance_id == build_items.size() + 1);
             build_items.emplace_back(instance_id, t);
 
             stream << "  </" << OBJECT_TAG << ">\n";
@@ -2045,13 +2076,13 @@ namespace Slic3r {
         return true;
     }
 
-    bool _3MF_Exporter::_add_model_config_file_to_archive(mz_zip_archive& archive, const Model& model)
+    bool _3MF_Exporter::_add_model_config_file_to_archive(mz_zip_archive& archive, const Model& model, const IdToObjectDataMap &objects_data)
     {
         std::stringstream stream;
         stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
         stream << "<" << CONFIG_TAG << ">\n";
 
-        for (const IdToObjectDataMap::value_type& obj_metadata : m_objects_data)
+        for (const IdToObjectDataMap::value_type& obj_metadata : objects_data)
         {
             const ModelObject* obj = obj_metadata.second.object;
             if (obj != nullptr)