Why do I have strange cuts/trims on walls? – Support site

Issue description

You notice that walls are unexpectedly cut or trimmed in 3D views and elevations. Some wall portions may be missing, or only part of the wall is trimmed. These anomalies are not visible on the floor plan but appear when viewing the model in elevation or 3D. The problem typically occurs after using the Trim Elements to Roof/Shell function with roofs consisting of multiple planes.

Solution

These irregular wall trims are usually caused by how the trimming operation interacts with multi-plane roofs, roof geometry, or wall height settings. The following are common scenarios and their solutions:

Only one roof plane selected from a multi-plane roof

If you trim a wall to a roof made up of multiple planes but only select a single plane during the operation, the trim will only recognize that one plane. This can result in half of the wall being cut away, not just the top, and the issue is only visible in elevation and 3D views

Select the wall you want to trim.
Use one of these methods to ensure all relevant roof planes are included:
- Select the wall and all roof planes together.
- Right-click and choose Connect > Trim Elements to Roof/Shell.
- In the dialog, confirm to use selected roofs as trimming elements.
Click Trim to execute the operation.
Review the result in 3D and elevation to confirm the wall is trimmed correctly.

For multi-plane roofs, always select the entire roof element, not just a single plane, before trimming.

Wall portion missing after trimming to roof

If a large section of the wall disappears after trimming, it is often because the roof does not fully cover the wall in plan or elevation. The trimming body of the roof only affects the area directly under the roof projection.

Check the alignment of the roof edges with the wall:
- In 3D or plan view, ensure the roof overhangs or at least matches the external face of the wall.
- Adjust the roof contour if needed so it fully covers the wall.
Re-trim the wall to the roof using Connect > Trim Elements to Roof/Shell.

Tip: Turn on Trimming Bodies in View > On-Screen View Options to visualize the area affected by the trim.

Only part of the wall is trimmed to the slope of the roof

If only a section of the wall is trimmed, the wall may not be tall enough for the roof to intersect it completely. The trim will only affect the area where the wall and the roof overlap in 3D space.

Select the wall and open Wall Settings.
Increase the wall height so it extends above the highest point of the roof plane it should be trimmed to.
Re-trim the wall using Connect > Trim Elements to Roof/Shell.

Tip: You can also resize the wall by using the stretch command in the pet palette..