Extrude surface distortion

Version 5 SR12 64-bit
(5.12.50810.13095, 10/08/2015)

Made a piece of U channel 101.0 x 50.5mm. Import curve from .ai file.
I have a surface that when extruded, some surfaces distort. (see attached 3dm)

I can fix it by deleting the 2 radius curves, _Arc , join, extrude …
Just not sure why the radius curve(s) in the surface caused the issue.

Extrude surface (Channel).3dm (76.9 KB)

It must have been something wrong with the curves . I sure dont much about imports and files . Might be a process of elimination in rebuildind the parts that made the extrusion. Good luck, Mark

There is no distortion in the geometry. I cut contours through the object and they are all identical. The apparent distortion is a artifact of the mesh settings. I changed the Mesh in Document Properties to “Smooth & slower” and the apparent distortion vanished. No idea what caused it. See attached file. Extrude surface (Channel) DC.3dm (328.9 KB)

Hi Tony - see if DivideAlongCreases > SplitAtTangents=Yes cleans that up without monkeying with mesh settings.’


If you read here, there is some more info on meshing problems/practices including internal G1 joints and the issues they may cause…

A relevant portion:

Problem: Joined tangent lines and arcs that have been extruded or revolved. Example - extruding a rounded rectangle. This forms a single surface with internal G1 areas, which the mesher struggles with. Solution: Explode the curves before extruding, or use Split > Isocurves at the G1 spots to create a structure with separate joined tangent surfaces instead of one single one. In the case of the extruded rounded rectangle, you will have eight joined surfaces, not one. In V5, you can use the Extrude command option SplitAtTangents=Yes to automatically split the resulting extrusion.


“DivideAlongCreases > SplitAtTangents=Yes”

That’s perfect, thanks.