Sketchup Round Corner Crack Top -

In the Round Corner toolbar, look for the Offset type (usually under Advanced settings).

Cracks often look like visible lines due to the "Soften Edges" setting.

To solve the SketchUp round corner crack top, you need to think like the plugin. Fredo6’s Round Corner works by creating three sets of geometry:

The crack appears when the plugin fails to triangulate the cap correctly. The primary causes are: sketchup round corner crack top

Before fixing the problem, you must understand it. The Round Corner plugin works by offsetting, extruding, and stitching geometry. When you apply a fillet to a hard edge, SketchUp’s geometry engine (based on polygons, not true NURBS curves) must triangulate complex intersections.

The "crack top" specifically occurs when the rounding algorithm fails to properly cap or weld the vertices on the uppermost horizontal plane. Instead of a continuous surface, you get:

This is most common when:

The Round Corner algorithm works by offsetting edges and trimming geometry. When you apply a fillet to a vertical edge that meets a flat top surface, the extension tries to blend the curve into the plane. If the radius of the corner is too large relative to the thickness of the top slab, the geometry collapses into itself, creating "cracks."

In short: The circle of the fillet is trying to eat into a space where there is no more geometry.

When the plugin fails entirely, do the fillet manually. In the Round Corner toolbar, look for the

This gives you total control and eliminates the crack because the top face never touched the rounding algorithm.

If you have already created the model and the crack exists, do not panic. Do not delete the whole thing. Here is the manual repair workflow.