You can separate the splittable part of a surface from its nonsplittable part
to identify the transition areas.
Before you begin: Open a 3D shape containing a set of surfaces suitable for being split.
Select Shading with Material in the View Modes dialog box
(View section of the action bar).
Click Split Analysis.
Select a surface or a set of surfaces.
If you select more than one surface, select Align to adjust all
the normals to the exterior.
In the Direction area, define the split direction. Otherwise,
the Z direction is taken by default.
Define the Positive draft angle and the Positive
tolerance angle.
The tolerance angle defines the transition area.
Click Apply.
You can see the splittable area in green color, the transition (gray wash) area in
yellow, and the nonsplittable area in red.
You can see the split line as the boundary between the red and the yellow area. If the
tolerance angle is 0, the curve represents the boundary between the red and the green
area.
Clear Shaded and select Pos. in the
Curves area to show only the split curve.
Select Shaded.
Optional:
Define a Negative draft angle and a Negative
tolerance angle.
in the View Modes dialog box
(View section of the action bar).
.