3D modelling

Round a solid edge

Select a solid edge and control its round with an exact radius.

About 4 minCadivari 0.3.0Watch and try

Useful first: Turn a sketch into a solid

A 3D Fillet changes the solid. Its radius must leave enough material around neighbouring faces and cavities. This is the Fillet tool in the 3D modelling rail, rather than the sketch corner tool.
A 3D Fillet changes the solid. Its radius must leave enough material around neighbouring faces and cavities. This is the Fillet tool in the 3D modelling rail, rather than the sketch corner tool.

A 3D Fillet changes the solid. Its radius must leave enough material around neighbouring faces and cavities. This is the Fillet tool in the 3D modelling rail, rather than the sketch corner tool.

Try it in Cadivari

  1. Open the edited block

    Use the body from the Push/Pull lesson, including its top-face edit. Keep the source sketch hidden so you can select the solid edge.

  2. Select a straight convex edge

    Click Fillet in the 3D tool rail. Select one continuous straight outer edge between two planar faces.

  3. Preview the radius

    Type a Radius of 2 mm. Inspect the preview from another angle. If it is invalid, read the task message and reduce the radius or reselect the edge.

  4. Apply the feature

    Choose Apply Fillet or press Enter. Select the saved feature to inspect its radius. Ctrl + Z undoes the operation.

Over to you

A small exercise

Apply a 2 mm Fillet to one top edge of the 15 mm block. Orbit the view and compare the rounded edge with a remaining sharp edge.

What you should see

One edge becomes rounded and the Fillet appears in the feature history. The body remains solid.

Things to look out for

  • The controls for a clean extrusion include multi-edge scopes. This exercise uses the single-edge workflow on an edited body.
  • A round that breaks into a wall or cavity can be rejected. A larger radius is not always valid.
Check your understandingWhich Fillet tool changes a solid edge

Use Fillet in the 3D modelling rail. The sketch Fillet tool rounds corners in drawing geometry.

With JavaScript enabled, you can save lesson completion in this browser.

Go deeper in the knowledge base

Instructions checked against the Cadivari 0.3.0 source and knowledge base on 2026-09-16. Lesson revision 1.