Trim boundaries

When surface data is imported and translated with Autodesk Inventor, faces can be trimmed in unexpected ways. To repair surfaces:

• Use Extract Loop to untrim surface loops.
• Use Boundary Trim to generate and rebuild a new surface using the surrounding surface edges or wires in the file.

Guidelines for extracting loops and trimming boundaries

The following is a typical workflow for repairing a loop using the Extract Loop and Boundary Trim commands.

1. An imported surface file is opened in the repair environment, and the find errors command reports a bad loop on the highlighted surface.
   Note Change the visibility of the surface to make selecting edges easier.
2. Use the Extract Loop command to remove the outer boundary, leaving the underlying surface exposed. Check Delete Wires to delete the original wires used to generate the trim, and then click Apply. The adjacent face edges are used to repair the face. Click Done.
3. On the ribbon, click Repair tabModify panel Boundary Trim.
4. Click Cutting Edges if it is not already selected, and select the first edge of the boundary. The red arrow in the Cutting Edges command changes to white when the first edge is selected. As you pause the cursor over an edge, its color changes to red. Only valid wires that intersect can be selected. When the edge is selected, the color changes to cyan (blue-green).
5. Continue selecting edges for the boundary, in a clockwise or counterclockwise direction, until the edges form a closed boundary. When all edges are selected, the color of the closed loop changes to black, and Loop or Face is enabled (its arrow turns red).
   Note Once the closed loop is formed, you cannot cancel the selection of any of the previously selected edges.
6. In the Boundary Trim dialog box, click Face or Loop if it is not already selected.
7. A preview of the surface is displayed. You can choose which side of the surface to keep.
8. Click Apply to trim the surface. Click Done after you trim all surfaces.

Use the Extract Loop command to untrim surface loops, exposing the underlying surface that is not trimmed by the original edges. You can optionally copy or delete the wires from the original surface edges depending whether they are to be used in repairing the surface. After you untrim the surface, you can use the edges of adjacent surfaces to trim the extracted surface. You can use Boundary Trim to generate and rebuild a new surface.

1. Data is translated into the repair environment, and the find errors command reports a bad loop on the highlighted surface in the repair environment.
   NoteChange the visibility of the surface to make selecting edges easier.
2. On the ribbon, click Repair tabModify panel Extract Loop.
3. Select the surface or an edge of the surface which you want to be untrimmed. The arrow color in the Loop command changes from red to white.
4. To specify that the existing edges of the surface are to become new wires, make sure the Delete Wires check box is cleared. Otherwise, check the Delete Wires check box to use adjacent face edges for trimming.
5. Click Apply. The untrimmed surface is equivalent to the bounding size of the surface.
6. Select another surface edge to extract, or click Done.