Sculpt: Grab Active Vertex and Dynamic Mesh Preview

Grab active vertex snaps the maximum strength of the grab brush to the highlighted active vertex, making it easier to manipulate low poly models or meshes with subdivision surfaces.
Dynamic Mesh Preview generates a list of connected vertices from the active vertex and draws them from the cursor code. This helps to visualize the real geometry the user is manipulating from sculpt mode when there are active modifiers.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D5646

release/scripts/startup/bl_ui/space_view3d_toolbar.py

@@ -380,6 +380,11 @@ class VIEW3D_PT_tools_brush(Panel, View3DPaintPanel):
             row = col.row()
             row.prop(brush, "use_automasking_topology")
 
+            if brush.sculpt_tool == 'GRAB':
+                col.separator()
+                row = col.row()
+                row.prop(brush, "grab_active_vertex")
+
             # topology_rake_factor
             if (
                     capabilities.has_topology_rake and