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When surfaces are exported from CAD systems that have a greater tolerance than Autodesk Inventor, they cannot be consumed by Autodesk Inventor because of their poor quality. These surfaces require manual repair before being used in part modeling. You can trim surfaces in the repair environment using selected edges or wires which form a closed trim boundary. You can also extract surface loops to replace a surface with one that is not trimmed by the original edges. Use this technique to use edges from adjacent surfaces to trim the untrimmed surface.
Trim surfaces with a closed boundary
Use Boundary Trim to clean and repair trimming curves that result from poorly translated surfaces. Boundary Trim rebuilds a surface to leverage wires or edges on adjacent surfaces. The edges and wires must create a closed loop for use as a new trimming curve, and they must be within the bounding area of the surface. The following is a typical workflow in which Boundary Trim repairs a translated surface:
- Extract one or more loops from a surface (using Extract Loop), leaving an untrimmed surface.
- Use the Boundary Trim command to rebuild the untrimmed surface.
Extract loops to untrim a surface
When you extract one or more loops, you untrim a surface, replacing it with one that is not trimmed by the original edges. Once extracted, the loops become wires, which, along with other wires or edges, can be used to form a new trimming curve
When the original wires have formed poor quality trimming curves, you can use the edges of other surfaces to form a trim boundary. You can also use a combination of the original wires and the edges of other surfaces. The Extract Loop command includes a Delete Wires option, so you can delete the existing edges of the surface rather than change them to wires.
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
- Only wires or edges of faces in the repair environment are valid selections.
- When a closed loop is formed, the color of the selected edges changes to the constrained sketch color (usually black).
- The Extract Loop command works only on a single face.
- Right-click to select an option to undo the last wire or edge selection.
The following is a typical workflow for repairing a loop using the Extract Loop and Boundary Trim commands.
- 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.
- 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.
- On the ribbon, click .
- 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).
- 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.
- In the Boundary Trim dialog box, click Face or Loop if it is not already selected.
- A preview of the surface is displayed. You can choose which side of the surface to keep.
- Click Apply to trim the surface. Click Done after you trim all surfaces.
Extract a loop
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.
- 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.
- On the ribbon, click .
- 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.
- 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.
- Click Apply. The untrimmed surface is equivalent to the bounding size of the surface.
- Select another surface edge to extract, or click Done.
Trim surfaces in the repair environment using surface edges or wires that form a closed boundary.
Click to select surface edges or wires to form a closed loop to be used as the new trim boundary.
Face or Loop
When selected edges form a closed boundary, Face is enabled. Select the part of the surface you want to keep during the trim operation.
When selected edges form a closed boundary, Loop is enabled. Select the loop on the surface you want to replace during the trim operation.
Extracts one or more loops by untrimming a surface, leaving the wires intact, and attempting to repair poor quality trimming curves. When extracted, loops are changed to wires.
Select a surface or an edge loop in the graphics window. The number of loops selected is displayed.
Select the check box to delete wires after extracting a loop. It is unselected by default.