2 files changed, 41 insertions, 12 deletions

diff --git a/release/scripts/startup/bl_ui/space_toolsystem_toolbar.py b/release/scripts/startup/bl_ui/space_toolsystem_toolbar.py
index e021433bee3..af263bf5d53 100644
--- a/release/scripts/startup/bl_ui/space_toolsystem_toolbar.py
+++ b/release/scripts/startup/bl_ui/space_toolsystem_toolbar.py
@@ -1304,22 +1304,30 @@ class _defs_sculpt:
 
     @ToolDef.from_fn
     def trim_box():
+        def draw_settings(_context, layout, tool):
+            props = tool.operator_properties("sculpt.trim_box_gesture")
+            layout.prop(props, "trim_mode", expand=False)
         return dict(
             idname="builtin.box_trim",
             label="Box Trim",
             icon="ops.sculpt.box_trim",
             widget=None,
             keymap=(),
+            draw_settings=draw_settings,
         )
 
     @ToolDef.from_fn
     def trim_lasso():
+        def draw_settings(_context, layout, tool):
+            props = tool.operator_properties("sculpt.trim_lasso_gesture")
+            layout.prop(props, "trim_mode", expand=False)
         return dict(
             idname="builtin.lasso_trim",
             label="Lasso Trim",
             icon="ops.sculpt.lasso_trim",
             widget=None,
             keymap=(),
+            draw_settings=draw_settings,
         )
 
     @ToolDef.from_fn
diff --git a/source/blender/editors/sculpt_paint/paint_mask.c b/source/blender/editors/sculpt_paint/paint_mask.c
index f7e8abde021..622ea82bf25 100644
--- a/source/blender/editors/sculpt_paint/paint_mask.c
+++ b/source/blender/editors/sculpt_paint/paint_mask.c
@@ -821,11 +821,24 @@ static void paint_mask_gesture_operator_properties(wmOperatorType *ot)
 typedef enum eSculptTrimOperationType {
   SCULPT_GESTURE_TRIM_INTERSECT,
   SCULPT_GESTURE_TRIM_DIFFERENCE,
+  SCULPT_GESTURE_TRIM_UNION,
+  SCULPT_GESTURE_TRIM_JOIN,
 } eSculptTrimOperationType;
 
+/* Intersect is not exposed in the UI because it does not work correctly with symmetry (it deletes
+ * the symmetrical part of the mesh in the first symmetry pass). */
 static EnumPropertyItem prop_trim_operation_types[] = {
-    {SCULPT_GESTURE_TRIM_INTERSECT, "INTERSECT", 0, "Intersect", ""},
-    {SCULPT_GESTURE_TRIM_DIFFERENCE, "DIFFERENCE", 0, "Difference", ""},
+    {SCULPT_GESTURE_TRIM_DIFFERENCE,
+     "DIFFERENCE",
+     0,
+     "Difference",
+     "Use a difference boolean operation"},
+    {SCULPT_GESTURE_TRIM_UNION, "UNION", 0, "Union", "Use a union boolean operation"},
+    {SCULPT_GESTURE_TRIM_JOIN,
+     "JOIN",
+     0,
+     "Join",
+     "Join the new mesh as separate geometry, without preforming any boolean operation"},
     {0, NULL, 0, NULL, NULL},
 };
 
@@ -1088,18 +1101,26 @@ static void sculpt_gesture_apply_trim(SculptGestureContext *sgcontext)
     }
   }
 
-  int boolean_mode;
-  switch (trim_operation->mode) {
-    case SCULPT_GESTURE_TRIM_INTERSECT:
-      boolean_mode = eBooleanModifierOp_Intersect;
-      break;
-    case SCULPT_GESTURE_TRIM_DIFFERENCE:
-      boolean_mode = eBooleanModifierOp_Difference;
-      break;
+  /* Join does not do a boolean operation, it just adds the geometry. */
+  if (trim_operation->mode != SCULPT_GESTURE_TRIM_JOIN) {
+    int boolean_mode = 0;
+    switch (trim_operation->mode) {
+      case SCULPT_GESTURE_TRIM_INTERSECT:
+        boolean_mode = eBooleanModifierOp_Intersect;
+        break;
+      case SCULPT_GESTURE_TRIM_DIFFERENCE:
+        boolean_mode = eBooleanModifierOp_Difference;
+        break;
+      case SCULPT_GESTURE_TRIM_UNION:
+        boolean_mode = eBooleanModifierOp_Union;
+        break;
+      case SCULPT_GESTURE_TRIM_JOIN:
+        BLI_assert(false);
+        break;
+    }
+    BM_mesh_boolean(bm, looptris, tottri, bm_face_isect_pair, NULL, 2, false, boolean_mode);
   }
 
-  BM_mesh_boolean(bm, looptris, tottri, bm_face_isect_pair, NULL, 2, false, boolean_mode);
-
   Mesh *result = BKE_mesh_from_bmesh_for_eval_nomain(bm, NULL, sculpt_mesh);
   BM_mesh_free(bm);
   result->runtime.cd_dirty_vert |= CD_MASK_NORMAL;