Sketchup Round Corner Crack | Top

Before you give up, try these solutions from simplest to most advanced.

If you are looking at a cracked top right now, do not panic. You do not need to re-model. Here are three repair methods, ranked from easiest to most advanced.

When you apply a RoundCorner (Fillet) operation to a shape—specifically a box or rectangle—the plugin successfully rounds the vertical edges. However, users frequently report that the top surface splits open or creates a jagged hole/crack right in the center of the face or at the corners.

Instead of a smooth, closed box, you are left with a model that looks like the top was ripped open.

This is the most reliable fix for a complex SketchUp round corner crack top. sketchup round corner crack top

Step 1: Make a copy of the top face.

Step 2: Thicken the copy.

Step 3: Intersect.

Step 4: Clean up.

If you are trying to use the Fredo6 RoundCorner plugin and it is failing, creating gaps, or literally "cracking" your geometry, here is how to fix it:

Common Causes for Geometry Breaking:

  • Intersecting Geometry: If you try to round a corner where two lines cross or overlap without a clean intersection, the plugin will fail.
  • Plugin Expiration: If you are using an old version of the RoundCorner plugin, it might have expired or be conflicting with a new SketchUp version.

    • Use this if you applied Round Corner to the top edge of a cylinder/box and it created a pinched or broken face on the top.

    Title: Round Corner creating a "cracked" or faceted top surface? (Fix inside) Before you give up, try these solutions from

    Body: I’m having an issue with the Round Corner extension (by Fredo6). I applied a rounded edge to the top of a cylinder, but instead of a smooth fillet, the top face is cracking / showing triangulation artifacts.

    The Problem: After running Round Corner, the top planar face develops weird lines, "cracks," or refuses to stay flat. It looks like the mesh is pinching at the center.

    Troubleshooting so far:

    Does anyone know how to keep the top face clean? Is this a geometry limit of SketchUp, or am I missing a setting in the Round Corner parameters? Step 2: Thicken the copy

    Solution I found (Posting for others): Nevermind, figured it out. You need to toggle the "Triangle Mesh" option OFF (or ON depending on the shape) in the Round Corner parameters. Alternatively, applying the round only to the vertical edge and leaving a tiny inset lip prevents the crack.

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