Bug: Persistent On Mesh Snap not working with 3D Face Tool

written up here:

Thanks Kyle. On SubD as a snap would be nice, but as I say it would be better just for the OnSrf / OnPolysrf to work fully. As the example, Polyline POnPSrf works to draw on a SubD. So it feels like everything is kinda there and working okay, but that there’s a gremlin of some kind in 3DFace where it sort of forgets the Persistent snaps.

agreed… we are digging into it-


I need to test it but - a caveat I forgot is that this worked fine in V6 actually. Which was why I was of the opinion it was a bug.

Hi Kyle,

I still don’t see this fixed - on the released v7.

@andy , I listened to you on the recent Simply Rhino webinar and you said this was a viable workflow. I still don’t see POnMesh or POnPsrf working with 3DFace command. That’s trying to create a SubD, or a Mesh Face. I still feel this would be a useful thing to have for, I guess I’d call, improved “direct modelling” of SubDs for certain cases. Getting Quick SubD starting points, taking advantage of chain/from edge etc, over the top of polysurfaces and meshes.

I reported this quite a long while back… I fired up V7 in the hope maybe it had been fixed.

Any chance it can be bumped up for a SR soon?

Because perhaps it will only be a bug fix rather than something ‘new’ to be developed.

@Jonathan_Hutchinson Thanks for being patient but steadfast on this. The 3DFace command was completely rewritten for Rhino 7. It is clear that it doesn’t work correctly together with PersistentOnMesh. And I’m sorry that I did not realize the severity of this issue before - I thought it was merely to do with tooltips not showing up corretly. I will look into this right away.

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@Jonathan_Hutchinson We added _SnapToMeshObject command to Rhino 7 for better retopology workflow. It lets you pick a mesh object that will be snapped to for the rest of the Rhino modelling session. You can change or disable that snap constraint by rerunning the command. This is also accessible from New in V7 toolbar and menu Tools - Object Snap - Snap to Mesh Object.


RH-58879 will be fixed in next Rhino 7 SR3 release candidate.

I’ve found another issue when constructing mesh geometry with 3DFace and using PersistentOnMesh or SnapToMeshObject. It is currently creating naked edges. I’m working on that now. This is logged as:
RH-62113 3DFace: Results in unwelded mesh edges when using mesh constraints

Thanks for looking into it Jussi. I knew I was right but couldn’t seem to convince John Brock initially that a bug existed. The SnapToMeshObject is nice to add also. I wonder if it could be redundant though if the persistent snaps get working again. I’m glad you have been able to see my point of view. Indeed, the tooltip did not work because the function did not work.

I’d really like to test out some drawn topology, as I do feel that Rhino has the ability to do something good in this area (and indeed I was right to think all the ingredients are about there).

Happy holidays,

Working much better on first look, thanks!

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