Gaps between surfaces when they are split by curves

An issue that I have always had but never figured out how to solve. When I split surfaces using a curve that is not a straight line, the surfaces break and gaps appear in the model, although the surface border indicates there should be no gap. I have tried DupBorder and Patch but it results in the same issue.

Test File.3dm (2.9 MB)

Hello - please see



Thank you! I changed the mesh settings to Smooth and Slower and although it is not perfect, it is much more accurate and the issue is barely noticeable unless zoomed in.

Just to be clear, does that mean that there is nothing wrong with the surfaces, and it is simply the mesh display? If so, why didn’t the grey surface have any issues?


For whatever reason, meshing on those edges was denser - use ShowRenderMesh/HideRenderMesh to see the polygons being used.


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