2 files changed, 33 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h
index b646d1d5e40..bfdafc3ad23 100644
--- a/source/blender/blenkernel/BKE_collection.h
+++ b/source/blender/blenkernel/BKE_collection.h
@@ -59,6 +59,7 @@ bool BKE_collection_object_remove(struct Main *bmain, struct ID *owner_id, struc
 bool BKE_collections_object_remove(struct Main *bmain, struct ID *owner_id, struct Object *object, const bool free_us);
 void BKE_collection_object_move(struct ID *owner_id, struct SceneCollection *sc_dst, struct SceneCollection *sc_src, struct Object *ob);
 bool BKE_collection_object_exists(struct SceneCollection *scene_collection, struct Object *ob);
+struct SceneCollection *BKE_collection_from_index(struct Scene *scene, const int index);
 
 struct Group *BKE_collection_group_create(struct Main *bmain, struct Scene *scene, struct LayerCollection *lc);
 
diff --git a/source/blender/blenkernel/intern/collection.c b/source/blender/blenkernel/intern/collection.c
index aed0ffb9fc3..669bbfb00cc 100644
--- a/source/blender/blenkernel/intern/collection.c
+++ b/source/blender/blenkernel/intern/collection.c
@@ -523,6 +523,38 @@ bool BKE_collection_object_exists(struct SceneCollection *scene_collection, stru
 	return false;
 }
 
+static SceneCollection *scene_collection_from_index_recursive(SceneCollection *scene_collection, const int index, int *index_current)
+{
+	if (index == (*index_current)) {
+		return scene_collection;
+	}
+
+	(*index_current)++;
+
+	for (SceneCollection *scene_collection_iter = scene_collection->scene_collections.first;
+	     scene_collection_iter != NULL;
+	     scene_collection_iter = scene_collection_iter->next)
+	{
+		SceneCollection *nested = scene_collection_from_index_recursive(scene_collection_iter, index, index_current);
+		if (nested != NULL) {
+			return nested;
+		}
+	}
+	return NULL;
+}
+
+/**
+ * Return Scene Collection for a given index.
+ *
+ * The index is calculated from top to bottom counting the children before the siblings.
+ */
+SceneCollection *BKE_collection_from_index(Scene *scene, const int index)
+{
+	int index_current = 0;
+	SceneCollection *master_collection = BKE_collection_master(&scene->id);
+	return scene_collection_from_index_recursive(master_collection, index, &index_current);
+}
+
 static void layer_collection_sync(LayerCollection *lc_dst, LayerCollection *lc_src)
 {
 	lc_dst->flag = lc_src->flag;