topic Sketch Changes When Used in Extrude in Inventor Forum

Sketch Changes When Used in Extrude

HishamWQ298 — Fri, 19 Jun 2026 19:32:53 GMT

Hey All,

I had a strange replicable phenomenon happen on a part inserted in an assembly, edited in context.

There is a sketch which I used for an extrude cut, which causes the sketch to change completely.

I projected the sketch to an origin plane and the same behavior is exhibited.

Can someone please let me know if this is similar to a past post or if they have any suggestions? I restarted Inventor already.

Schrödinger's Sketch.mp4

EDIT: I bypassed this issue by breaking the projected link on the projected sketch and that seemed to work. It seems the sketch has something to do with the part geometry which changes once the extrude is made, causing the sketch itself to change. So technically this could be a cyclical constraint which Inventor didn't recognize.

Even with that workaround, the original sketch changed and broke.

Thanks,

Hisham

Re: Sketch Changes When Used in Extrude

Yijiang.Cai — Thu, 25 Jun 2026 06:24:15 GMT

@HishamWQ298 it looks an issue to me! If possible, could you please share the dataset with me via river-yijiang.cai@autodesk.com? That will help us further investigate the issue. Many thanks!

Re: Sketch Changes When Used in Extrude

piotrekdoro94 — Thu, 25 Jun 2026 08:39:56 GMT

I encounter a similar problem semi-regularly. When I make an extrusion using curved/eliptical/spline profile, make the walls of the extrusion slanted and try to constrain a line to be tangent or perpendicular to the projected geometry.

Unfortunately it seems like a bug with the Inventor's constraint solver and it's probably here to stay since I'm on Inventor 2016 version. The only thing that works for me is deleting the projected constraint (as you did) or unconstraining the sketch right before doing anything with it.