Remove fillets and chamfers

A CAD model softens its edges: a fillet is a narrow rounded face between two others, a chamfer a narrow flat one. For a picture on the web they cost a lot of triangles and show little. This tool takes them off and makes the edge sharp again: the two faces the blend ran between are extended until they meet, and the blend is gone. Where three fillets meet at a corner, the patch between them goes too and the corner is the point where the three faces meet.

It needs the CAD faces, so it works on a part from a STEP file opened with them (see CAD faces and edges), or from a scene saved from one. The CAD faces say what each face is and which faces meet tangent, which is how a fillet is told from a small cylinder that is part of the shape. A part without them says so.

How to use it

• Select the parts and run Remove fillets and chamfers from the command search (Ctrl + K). With nothing selected it runs on every part that is shown.
• The card that opens has two limits, as shares of the part's size: Fillets up to (a radius) and Chamfers up to (a width). A blend wider than its limit stays. 0 leaves that kind alone. A change runs it again from the part as it was.
• The card says how many fillets and chamfers went, and how many blend faces were left and why.
• One undo step (Ctrl + Z) brings the part back.

What is left alone

• A blend between faces that are not planes or cylinders (a cone, a sphere, a free-form surface).
• A corner where four or more faces meet at one point, or a blend that runs into another kind of face along its length.
• A blend whose rim would have to move further than a few times its own size: the faces beside it did not fit.
• A blend that touches, at a point, a blend that was already taken off and could not be done together with it: moving that point again would tear the face.