source/blender/modifiers/intern/MOD_grease_pencil_opacity.cc

@@ -317,12 +317,14 @@ static void blend_write(BlendWriter *writer, const ID * /*id_owner*/, const Modi
   const GreasePencilOpacityModifierData *omd = (const GreasePencilOpacityModifierData *)md;
 
   BLO_write_struct(writer, GreasePencilOpacityModifierData, omd);
+  greasepencil::write_influence_data(writer, &omd->influence);
 }
 
 static void blend_read(BlendDataReader *reader, ModifierData *md)
 {
   GreasePencilOpacityModifierData *omd = (GreasePencilOpacityModifierData *)md;
-  UNUSED_VARS(reader, omd);
+
+  greasepencil::read_influence_data(reader, &omd->influence);
 }
 
 }  // namespace blender

source/blender/modifiers/intern/MOD_grease_pencil_util.cc

@@ -21,6 +21,8 @@
 #include "BKE_lib_query.h"
 #include "BKE_material.h"
 
+#include "BLO_read_write.hh"
+
 #include "DNA_defaults.h"
 
 #include "DEG_depsgraph_query.hh"
@@ -70,6 +72,23 @@ void foreach_influence_ID_link(GreasePencilModifierInfluenceData *influence_data
   walk(user_data, ob, (ID **)&influence_data->material, IDWALK_CB_USER);
 }
 
+void write_influence_data(BlendWriter *writer,
+                          const GreasePencilModifierInfluenceData *influence_data)
+{
+  if (influence_data->custom_curve) {
+    BKE_curvemapping_blend_write(writer, influence_data->custom_curve);
+  }
+}
+
+void read_influence_data(BlendDataReader *reader,
+                         GreasePencilModifierInfluenceData *influence_data)
+{
+  BLO_read_data_address(reader, &influence_data->custom_curve);
+  if (influence_data->custom_curve) {
+    BKE_curvemapping_blend_read(reader, influence_data->custom_curve);
+  }
+}
+
 void draw_layer_filter_settings(const bContext * /*C*/, uiLayout *layout, PointerRNA *ptr)
 {
   PointerRNA ob_ptr = RNA_pointer_create(ptr->owner_id, &RNA_Object, ptr->owner_id);

source/blender/modifiers/intern/MOD_grease_pencil_util.hh

@@ -40,6 +40,10 @@ void foreach_influence_ID_link(GreasePencilModifierInfluenceData *influence_data
                                Object *ob,
                                IDWalkFunc walk,
                                void *user_data);
+void write_influence_data(BlendWriter *writer,
+                          const GreasePencilModifierInfluenceData *influence_data);
+void read_influence_data(BlendDataReader *reader,
+                         GreasePencilModifierInfluenceData *influence_data);
 
 void draw_layer_filter_settings(const bContext *C, uiLayout *layout, PointerRNA *ptr);
 void draw_material_filter_settings(const bContext *C, uiLayout *layout, PointerRNA *ptr);