[quote=“jeff_hammond, post:17, topic:7263”]

if you taper perpendicular to a 2D circle then yes, the offset will remain constant & on the same angle… draw a circle on the XY plane then taper it vertically… you’ll end up with a circle inside a circle…

i’m not really sure what you mean by "*the offset is normal to the direction of the tapered extrusion as well as to the curve.* "

i’ll re-read it in the morning though… this is getting confusing

[/quote]But if the taper is not perpendicular to a planar surface, including a circle, then the offset will not remain at the same angle to the direction of the taper… draw a circle on the XY plane then taper it in a non-vertical direction… you will not end up with a circle inside a circle…

I’ll try another explanation of an offset, non-planar curve. Corresponding points between the original curve and the offset curve will lie on:

- A plane passing through the point on the original curve and perpendicular to the original curve
- A plane parallel to the plane determining the offset direction. In the case of a tapered extrusion the this plane will be normal to the extrusion direction.

See the attached file for an example.TaperedExt03.3dm (143.5 KB)