Whence the discrepancy when using ExtrudeSubD with faces and edges with the N (normal) option? The middle face/edge extrusion directions are congruent (top view), but not those of the outer ones. [Untitled-27] [Untitled-28]

Perhaps an option to switch between both styles will be the best solution to everybody.

Still, hard to explain the discrepancy to someone transitioning from Maya or 3ds, for example.

I don’t have an explanation for why this is like that, probably these tools were coded at different times by different people. Or the commands copied the behavior that was already existing in Rhino for Breps or Meshes. I don’t know for sure, but I think both commands could be made to use either or …

Seems like others have already asked for ExtrudeSubD on Faces to use the face normal for vertices on the boundary of the selection (i.e. like ExtrudeSubD for Edges`): RH-76783 ExtrudeSubD extruding faces issue

I would expect a vertex normal extrusion behaviour by default; a face normal extrusion is more like what you do with the Gumball only. In any case, a mix of both, when extruding from an edge, is in my opinion somewhat confusing.

So the opposite of what was logged in the YouTrack issue I linked to. I guess we’re really going to need an option to switch between the two behaviors so everyone can choose what they want. Thank you for reporting this.

And, please, allow the user to specify X, Y, Z, and normal direction for Trim and MatchSrf with the On surface option ; ) [Untitled-107]

@Lagom do these cover what you want for MatchSrf? RH-48653 MatchSrf: Added OnSurface option to first prompt RH-88052 MatchSrf - constrain direction RH-87874 MatchSrf direction needs better control For Trim, I would use the ApparentIntersections in the appropriate viewport / CPlane to get the X Y…

Thanks, normal in Alias, etc. is what in Rhinospeak is called “pull” I believe.

ExtrudeSubD faces vs edges

Rhino SubD

brian (Brian Gillespie) September 24, 2025, 12:17am 12

RH-48653 is fixed in Rhino WIP

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ExtrudeSubD faces vs edges

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