Trim a regular surface then convert a four-sided trim region into an untrimmed surface

Trims a surface and converts the trimmed surface to a natural surface with the same shape, in one operation.

1. Choose Surface Edit > Trim > Trim Convert.
2. Select a surface which has curves-on-surface defining closed regions. (You can only trim convert one surface at a time.)
   Note:

   If 3D Trimming is turned on, you can either select curves to project onto the surface, or cross sections, to define the trim regions. You can also select a vector option. If you are trimming a surface with its own cross-sections, choose Normal as the vector option.

3. Click on the regions to keep. Make sure that those regions define a four-sided surface.

   Crosshairs appear on the selected regions. (The size of those region selectors can be modified through the option window.)

   
4. Click the Convert button

   The tool trims the surface, then attempts to convert the trimmed surface to a new surface with natural boundaries.

   Note:

   If the trimmed surface is not four-sided, the system issues an error and asks you to redefine the trim region.

   If Show Surface Deviation is turned on, a locator shows the maximum deviation between the original and the converted surface.

   
5. If you are not happy with the result, click the Revert button to get back the original untrimmed surface.