diff --git a/source/blender/makesdna/DNA_defaults.h b/source/blender/makesdna/DNA_defaults.h
index ef7f573e7a8..b2d38bc849c 100644
--- a/source/blender/makesdna/DNA_defaults.h
+++ b/source/blender/makesdna/DNA_defaults.h
@@ -40,6 +40,8 @@ uint8_t *_DNA_struct_default_alloc_impl(const uint8_t *data_src,
                                         size_t size,
                                         const char *alloc_str);
 
+uint8_t *_DNA_struct_default_alloc_from_nr_impl(const int nr, const char *alloc_str);
+
 /**
  * Wrap with macro that casts correctly.
  */
@@ -52,6 +54,9 @@ uint8_t *_DNA_struct_default_alloc_impl(const uint8_t *data_src,
       sizeof(struct_name), \
       __func__)
 
+#define DNA_struct_default_alloc_from_nr(nr) \
+  (void *)_DNA_struct_default_alloc_from_nr_impl(nr, __func__)
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/makesdna/intern/dna_defaults.c b/source/blender/makesdna/intern/dna_defaults.c
index fd23c5c618f..99cedaa22c4 100644
--- a/source/blender/makesdna/intern/dna_defaults.c
+++ b/source/blender/makesdna/intern/dna_defaults.c
@@ -85,6 +85,8 @@
 #include "IMB_imbuf.h"
 
 #include "DNA_defaults.h"
+#include "DNA_genfile.h"
+#include "DNA_sdna_types.h"
 
 #include "DNA_armature_types.h"
 #include "DNA_asset_types.h"
@@ -583,3 +585,20 @@ uint8_t *_DNA_struct_default_alloc_impl(const uint8_t *data_src,
   memcpy(data_dst, data_src, size);
   return data_dst;
 }
+
+uint8_t *_DNA_struct_default_alloc_from_nr_impl(const int nr, const char *alloc_str)
+{
+  const SDNA *sdna = DNA_sdna_current_get();
+  BLI_assert((nr >= 0) && (nr < sdna->structs_len));
+  const SDNA_Struct *struct_info = sdna->structs[nr];
+  const size_t size = sdna->types_size[struct_info->type];
+  uint8_t *data_dst = MEM_mallocN(size, alloc_str);
+  const uint8_t *data_src = DNA_default_table[nr];
+  if (data_src) {
+    memcpy(data_dst, data_src, size);
+  }
+  else {
+    memset(data_dst, 0x0, size);
+  }
+  return data_dst;
+}
diff --git a/source/blender/makesrna/RNA_access.h b/source/blender/makesrna/RNA_access.h
index 47afa0f9a13..12bb125385b 100644
--- a/source/blender/makesrna/RNA_access.h
+++ b/source/blender/makesrna/RNA_access.h
@@ -830,6 +830,12 @@ void RNA_struct_py_type_set(StructRNA *srna, void *py_type);
 void *RNA_struct_blender_type_get(StructRNA *srna);
 void RNA_struct_blender_type_set(StructRNA *srna, void *blender_type);
 
+/**
+ * \return the DNA index compatible with #DNA_struct_find_nr
+ * or -1 when there is no associated struct.
+ */
+int RNA_struct_dna_index_get(const StructRNA *srna);
+
 struct IDProperty **RNA_struct_idprops_p(PointerRNA *ptr);
 struct IDProperty *RNA_struct_idprops(PointerRNA *ptr, bool create);
 bool RNA_struct_idprops_check(StructRNA *srna);
diff --git a/source/blender/makesrna/RNA_types.h b/source/blender/makesrna/RNA_types.h
index e37eb9f7188..d9c2ef9752b 100644
--- a/source/blender/makesrna/RNA_types.h
+++ b/source/blender/makesrna/RNA_types.h
@@ -374,6 +374,11 @@ typedef enum ParameterFlag {
    * \note only for input parameters!
    */
   PARM_PYFUNC_OPTIONAL = (1 << 3),
+  /**
+   * Support coercing dictionary into RNA structs (for Python).
+   * The struct must either be part of DNA or use ID-properties such as "OperatorProperties".
+   */
+  PARM_RNAPTR_COERCE = (1 << 4),
 } ParameterFlag;
 
 struct CollectionPropertyIterator;
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 0fadbda5a18..50028aa89e6 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -4271,7 +4271,7 @@ static void rna_generate_struct(BlenderRNA *UNUSED(brna), StructRNA *srna, FILE
   fprintf(f, "\t");
   rna_print_c_string(f, srna->identifier);
   fprintf(f, ", NULL, NULL"); /* PyType - Can't initialize here */
-  fprintf(f, ", %d, NULL, ", srna->flag);
+  fprintf(f, ", %d, %d, NULL, ", srna->dna_index, srna->flag);
   rna_print_c_string(f, srna->name);
   fprintf(f, ",\n\t");
   rna_print_c_string(f, srna->description);
diff --git a/source/blender/makesrna/intern/rna_access.c b/source/blender/makesrna/intern/rna_access.c
index 63eb016b5de..243584915c3 100644
--- a/source/blender/makesrna/intern/rna_access.c
+++ b/source/blender/makesrna/intern/rna_access.c
@@ -914,6 +914,11 @@ void RNA_struct_blender_type_set(StructRNA *srna, void *blender_type)
   srna->blender_type = blender_type;
 }
 
+int RNA_struct_dna_index_get(const StructRNA *srna)
+{
+  return srna->dna_index;
+}
+
 char *RNA_struct_name_get_alloc(PointerRNA *ptr, char *fixedbuf, int fixedlen, int *r_len)
 {
   PropertyRNA *nameprop;
diff --git a/source/blender/makesrna/intern/rna_define.c b/source/blender/makesrna/intern/rna_define.c
index b17ca7d8d59..68a421007f2 100644
--- a/source/blender/makesrna/intern/rna_define.c
+++ b/source/blender/makesrna/intern/rna_define.c
@@ -1084,6 +1084,9 @@ void RNA_def_struct_sdna(StructRNA *srna, const char *structname)
 #endif
 
   ds->dnaname = structname;
+
+  /* May by -1, which is fine. */
+  srna->dna_index = DNA_struct_find_nr_wrapper(DefRNA.sdna, structname);
 }
 
 void RNA_def_struct_sdna_from(StructRNA *srna, const char *structname, const char *propname)
@@ -1535,6 +1538,10 @@ void RNA_def_parameter_flags(PropertyRNA *prop,
 {
   prop->flag |= flag_property;
   prop->flag_parameter |= flag_parameter;
+
+  if (flag_parameter & PARM_RNAPTR_COERCE) {
+    BLI_assert(prop->type == PROP_POINTER);
+  }
 }
 
 void RNA_def_parameter_clear_flags(PropertyRNA *prop,
diff --git a/source/blender/makesrna/intern/rna_image.c b/source/blender/makesrna/intern/rna_image.c
index af13baad5a2..745b12f1e1f 100644
--- a/source/blender/makesrna/intern/rna_image.c
+++ b/source/blender/makesrna/intern/rna_image.c
@@ -709,17 +709,17 @@ static void rna_def_imageuser(BlenderRNA *brna)
 
   prop = RNA_def_property(srna, "multilayer_layer", PROP_INT, PROP_UNSIGNED);
   RNA_def_property_int_sdna(prop, NULL, "layer");
-  RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
+  // RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
   RNA_def_property_ui_text(prop, "Layer", "Layer in multilayer image");
 
   prop = RNA_def_property(srna, "multilayer_pass", PROP_INT, PROP_UNSIGNED);
   RNA_def_property_int_sdna(prop, NULL, "pass");
-  RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
+  // RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
   RNA_def_property_ui_text(prop, "Pass", "Pass in multilayer image");
 
   prop = RNA_def_property(srna, "multilayer_view", PROP_INT, PROP_UNSIGNED);
   RNA_def_property_int_sdna(prop, NULL, "view");
-  RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
+  // RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* image_multi_cb */
   RNA_def_property_ui_text(prop, "View", "View in multilayer image");
 
   prop = RNA_def_property(srna, "tile", PROP_INT, PROP_UNSIGNED);
diff --git a/source/blender/makesrna/intern/rna_image_api.c b/source/blender/makesrna/intern/rna_image_api.c
index 1c04805be8b..364a50f6b11 100644
--- a/source/blender/makesrna/intern/rna_image_api.c
+++ b/source/blender/makesrna/intern/rna_image_api.c
@@ -61,8 +61,12 @@ static void rna_ImagePackedFile_save(ImagePackedFile *imapf, Main *bmain, Report
   }
 }
 
-static void rna_Image_save_render(
-    Image *image, bContext *C, ReportList *reports, const char *path, Scene *scene)
+static void rna_Image_save_render(Image *image,
+                                  bContext *C,
+                                  ReportList *reports,
+                                  const char *path,
+                                  Scene *scene,
+                                  ImageUser *iuser)
 {
   ImBuf *ibuf;
 
@@ -71,12 +75,16 @@ static void rna_Image_save_render(
   }
 
   if (scene) {
-    ImageUser iuser = {NULL};
+    ImageUser iuser_copy = *iuser;
     void *lock;
 
-    iuser.scene = scene;
+    if (iuser_copy.scene == NULL) {
+      iuser_copy.scene = scene;
+    }
+
+    printf("iuser_copy: %d %d %d\n", iuser_copy.view, iuser_copy.layer, iuser_copy.pass);
 
-    ibuf = BKE_image_acquire_ibuf(image, &iuser, &lock);
+    ibuf = BKE_image_acquire_ibuf(image, &iuser_copy, &lock);
 
     if (ibuf == NULL) {
       BKE_report(reports, RPT_ERROR, "Could not acquire buffer from image");
@@ -291,6 +299,8 @@ void RNA_api_image(StructRNA *srna)
   parm = RNA_def_string_file_path(func, "filepath", NULL, 0, "", "Save path");
   RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
   RNA_def_pointer(func, "scene", "Scene", "", "Scene to take image parameters from");
+  parm = RNA_def_pointer(func, "image_user", "ImageUser", "", "Image user for saving");
+  RNA_def_parameter_flags(parm, 0, PARM_RNAPTR_COERCE);
 
   func = RNA_def_function(srna, "save", "rna_Image_save");
   RNA_def_function_ui_description(func, "Save image to its source path");
diff --git a/source/blender/makesrna/intern/rna_internal_types.h b/source/blender/makesrna/intern/rna_internal_types.h
index 723ae384fdf..a744d5b6684 100644
--- a/source/blender/makesrna/intern/rna_internal_types.h
+++ b/source/blender/makesrna/intern/rna_internal_types.h
@@ -513,6 +513,9 @@ struct StructRNA {
   void *py_type;
   void *blender_type;
 
+  /** Index in (-1 when not DNA). */
+  int dna_index;
+
   /* various options */
   int flag;
   /* Each StructRNA type can define own tags which properties can set
diff --git a/source/blender/python/intern/CMakeLists.txt b/source/blender/python/intern/CMakeLists.txt
index 2be2105d327..3c000921667 100644
--- a/source/blender/python/intern/CMakeLists.txt
+++ b/source/blender/python/intern/CMakeLists.txt
@@ -35,6 +35,9 @@ set(INC
   ../../../../intern/guardedalloc
   ../../../../intern/mantaflow/extern
   ../../../../intern/opencolorio
+
+  # dna_type_offsets.h
+  ${CMAKE_CURRENT_BINARY_DIR}/../../makesdna/intern
 )
 
 set(INC_SYS
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index a79a0ed32bf..efd7a4d8ade 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -31,6 +31,7 @@
 
 #include "RNA_types.h"
 
+#include "BLI_alloca.h"
 #include "BLI_bitmap.h"
 #include "BLI_dynstr.h"
 #include "BLI_listbase.h"
@@ -56,6 +57,8 @@
 #include "RNA_define.h" /* RNA_def_property_free_identifier */
 #include "RNA_enum_types.h"
 
+#include "DNA_defaults.h"
+
 #include "CLG_log.h"
 
 #include "MEM_guardedalloc.h"
@@ -1501,6 +1504,14 @@ int pyrna_pydict_to_props(PointerRNA *ptr,
         error_val = -1; /* pyrna_py_to_prop sets the error. */
         break;
       }
+      if (RNA_property_flag(prop) & PROP_NEVER_NULL) {
+        PyErr_Format(PyExc_TypeError,
+                     "%.200s: keyword \"%.200s\" isn't set but is marked NEVER NULL",
+                     error_prefix,
+                     arg_name ? arg_name : "<UNKNOWN>");
+        error_val = -1; /* pyrna_py_to_prop sets the error. */
+        break;
+      }
     }
     else {
       if (pyrna_py_to_prop(ptr, prop, NULL, item, error_prefix)) {
@@ -1534,6 +1545,24 @@ int pyrna_pydict_to_props(PointerRNA *ptr,
   return error_val;
 }
 
+static PyObject *pyrna_pydict_to_ptr_alloc(PointerRNA *ptr,
+                                           PropertyRNA *prop,
+                                           PyObject *value,
+                                           const char *error_prefix)
+{
+  StructRNA *ptr_type = RNA_property_pointer_type(ptr, prop);
+  const int nr = RNA_struct_dna_index_get(ptr_type);
+  BLI_assert(nr != -1);
+  uint8_t *data = DNA_struct_default_alloc_from_nr(nr);
+  PointerRNA value_ptr;
+  RNA_pointer_create(NULL, ptr_type, data, &value_ptr);
+  if (pyrna_pydict_to_props(&value_ptr, value, false, error_prefix) == -1) {
+    MEM_freeN(data);
+    return NULL;
+  }
+  return pyrna_struct_CreatePyObject(&value_ptr);
+}
+
 static PyObject *pyrna_func_to_py(const PointerRNA *ptr, FunctionRNA *func)
 {
   BPy_FunctionRNA *pyfunc = (BPy_FunctionRNA *)PyObject_NEW(BPy_FunctionRNA, &pyrna_func_Type);
@@ -6031,6 +6060,36 @@ static PyObject *small_dict_get_item_string(PyObject *dict, const char *key_look
   return NULL;
 }
 
+/**
+ * \param parm_index: The argument index or -1 for keyword arguments.
+ */
+static void pyrna_func_error_prefix(BPy_FunctionRNA *self,
+                                    PropertyRNA *parm,
+                                    const int parm_index,
+                                    char *error,
+                                    const size_t error_size)
+{
+  PointerRNA *self_ptr = &self->ptr;
+  FunctionRNA *self_func = self->func;
+  if (parm_index == -1) {
+    BLI_snprintf(error,
+                 error_size,
+                 "%.200s.%.200s(): error with keyword argument \"%.200s\" - ",
+                 RNA_struct_identifier(self_ptr->type),
+                 RNA_function_identifier(self_func),
+                 RNA_property_identifier(parm));
+  }
+  else {
+    BLI_snprintf(error,
+                 error_size,
+                 "%.200s.%.200s(): error with argument %d, \"%.200s\" - ",
+                 RNA_struct_identifier(self_ptr->type),
+                 RNA_function_identifier(self_func),
+                 parm_index,
+                 RNA_property_identifier(parm));
+  }
+}
+
 static PyObject *pyrna_func_call(BPy_FunctionRNA *self, PyObject *args, PyObject *kw)
 {
   /* NOTE: both BPy_StructRNA and BPy_PropertyRNA can be used here. */
@@ -6047,6 +6106,8 @@ static PyObject *pyrna_func_call(BPy_FunctionRNA *self, PyObject *args, PyObject
 
   PropertyRNA *pret_single = NULL;
   void *retdata_single = NULL;
+  BPy_StructRNA **items_alloc = NULL;
+  int items_alloc_count = 0;
 
   /* enable this so all strings are copied and freed after calling.
    * this exposes bugs where the pointer to the string is held and re-used */
@@ -6180,32 +6241,34 @@ static PyObject *pyrna_func_call(BPy_FunctionRNA *self, PyObject *args, PyObject
       }
     }
 #endif
-    err = pyrna_py_to_prop(&funcptr, parm, iter.data, item, "");
-
-    if (err != 0) {
-      /* the error generated isn't that useful, so generate it again with a useful prefix
-       * could also write a function to prepend to error messages */
-      char error_prefix[512];
-      PyErr_Clear(); /* Re-raise. */
 
-      if (kw_arg == true) {
-        BLI_snprintf(error_prefix,
-                     sizeof(error_prefix),
-                     "%.200s.%.200s(): error with keyword argument \"%.200s\" - ",
-                     RNA_struct_identifier(self_ptr->type),
-                     RNA_function_identifier(self_func),
-                     RNA_property_identifier(parm));
+    /* The error generated isn't that useful, so generate it again with a useful prefix
+     * could also write a function to prepend to error messages. */
+    char error_prefix[512];
+
+    if ((flag_parameter & PARM_RNAPTR_COERCE) && PyDict_CheckExact(item)) {
+      const PropertyType type = RNA_property_type(parm);
+      BLI_assert(type == PROP_POINTER);
+      item = pyrna_pydict_to_ptr_alloc(&funcptr, parm, item, "");
+      if (item == NULL) {
+        PyErr_Clear(); /* Re-raise. */
+        pyrna_func_error_prefix(self, parm, kw_arg ? -1 : i, error_prefix, sizeof(error_prefix));
+        pyrna_pydict_to_ptr_alloc(&funcptr, parm, item, error_prefix);
+        err = -1;
+        break;
       }
-      else {
-        BLI_snprintf(error_prefix,
-                     sizeof(error_prefix),
-                     "%.200s.%.200s(): error with argument %d, \"%.200s\" - ",
-                     RNA_struct_identifier(self_ptr->type),
-                     RNA_function_identifier(self_func),
-                     i,
-                     RNA_property_identifier(parm));
+      /* Allocate once (normally `alloca` is avoided in a loop). */
+      if (items_alloc == NULL) {
+        items_alloc = BLI_array_alloca(items_alloc, parms_len);
       }
+      items_alloc[items_alloc_count++] = (BPy_StructRNA *)item;
+    }
 
+    err = pyrna_py_to_prop(&funcptr, parm, iter.data, item, "");
+
+    if (err != 0) {
+      PyErr_Clear(); /* Re-raise. */
+      pyrna_func_error_prefix(self, parm, kw_arg ? -1 : i, error_prefix, sizeof(error_prefix));
       pyrna_py_to_prop(&funcptr, parm, iter.data, item, error_prefix);
 
       break;
@@ -6351,6 +6414,15 @@ static PyObject *pyrna_func_call(BPy_FunctionRNA *self, PyObject *args, PyObject
   RNA_parameter_list_end(&iter);
   RNA_parameter_list_free(&parms);
 
+  /* Cleanup any coerced arguments. */
+  while (UNLIKELY(--items_alloc_count >= 0)) {
+    item = (PyObject *)items_alloc[items_alloc_count];
+    BLI_assert(item->ob_refcnt == 1);
+    MEM_freeN(((BPy_StructRNA *)item)->ptr.data);
+    ((BPy_StructRNA *)item)->ptr.data = NULL;
+    Py_DECREF((PyObject *)item);
+  }
+
   if (ret) {
     return ret;
   }