Free Autodesk Civil 3D App


KeySurfaceFix is a free app, developed by Keysoft Solutions and available to download from the Autodesk App Store.

KeySurfaceFix runs inside Autodesk Civil 3D only and allows you to scan surface models within the current drawing for holes and fill these so that your surface accurately reflects the existing site or your design proposals.

How do holes appear in my model?

When working with Civil 3D surfaces, occasionally holes are created as a result of an error during editing. The most common cause is mistakenly deleting interior triangle lines, although holes can be introduced when surfaces with non-matching boundaries are pasted together, or where feature lines have too few vertices and the resulting triangulation does not accurately match boundaries.


Why should I correct holes in my model?

A hole in a surface is treated by Civil 3D as a void in the model. Voids can cause errors in earthwork calculations, generate broken contours and appear as gaps in visualisations. Also, they can impact on the performance.


It is not always easy to detect holes in a Civil surface and a simple check can be to display the triangulation in a shaded or rendered view once in a while when the hole will be more obvious. Even then, small holes in the surface may be difficult to see.


How Does KeySurfaceFix Work?

When a hole is detected, KeySurfaceFix will analyse the geometry surrounding the hole, insert a point within the boundary and rebuild the Civil surface.


For more information on how to use KeySurfaceFix, visit our help site: