Controlling part of an object with curve(s) + Importing with crease

Hello. appreciations for your supports.
my questions:
1- is there a way to use curves to control ONLY a selection of sub-objects (points/faces/edges) like what’s in maya called wire deformer or selection groups in blender?
it’s would be a great advantage for us, because we design classic furniture that often has details that have curvature, and it takes effort having to switch between rhino and other softwares to fix them.

2- I’ve tried importing mesh objects into rhino preserving creases to then convert to SubD, but I get a mesh with all edges creased. is there a way to preserve creases in rhino while importing?


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regarding 1: There are no such tools in Rhino, can you show an example of how you are using these tools to accomplish your design goal?
regarding 2: Can you send an example file that you try to import that has creases and show how it should look?

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You could move a selection of control points with Grasshopper.

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Yes sure;
1- First I export my model from rhino to Maya (or blender, principles are the same). Then I make it a live surface so I can draw curves directly on it (the same as Snap On mesh in WIP which is a great advantage).

Then I add a wire deformer between my curve and mesh (which makes a history node with editable parameters anytime I want them; (I wish to see this node based history recording in future Rhinos!)

then I specify a Drop-off distance and start moving curve control points around.

it also has some other parameters like rotation (based on curve tangent) and scale and I can also paint points with values between 0 and 1 to exclude the influence with more control.

also we can add as much wire deformers as we want and have individual parameters for each.
this non-destructive workflow helps us manage plan changes better in the process, until final confirmation.

2- my respects:
Creased Model.fbx (71.9 KB)
this is the creased model exported from Maya. it looks good in Maya/blender import but the creases are lost in rhino and we have to reassign them; so this workflow becomes likely impractical.

this is how it should look:

By the way I found a possible solution inside rhino for the first case, but it needs enhancements in terms of performance, advanced controls and ease of use:

I built a curve on my mesh, and then made a double direction extrude so it covered my target. then I used Cage command and selected the resulting surface as the cage and set Deformation parameter as Fast. unfortunately the performance wasn’t pleasant while moving the control points which is understandable as my mesh was somewhat dense. but performance was good in Maya so I think improvement is possible.

I also Used Flow along curve command with Local = Yes and despite it is useful but It’s a little time consuming and I figured out it doesn’t record history when Local is Yes.

Uploading: Screenshot (66).png…

There is something else inside Maya which is very useful for a big variety of situations I wish you have an eye on for your Future updates. that’s called Proximity deformer.
in simple it is the cage command from custom simple shapes. I think in rhino it would be good to give the ability of extracting cages from a mesh.

CageEdit command allows a NURBS curve, surface or polysurface to be used as the control object. A single edge of a mesh or a single edge of a SubD surface can also be used as the control object.

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you can still use the _SoftTransform function

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@Carl_starling after some investigation, it seems the crease is not importing correctly, was fixed some time ago but is broken in the current versions of Rhino 7 and 8. Logged as RH-57242 FBX import - SubD creases are not added properly

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Thank you all for your kind answers.
I find that using NURBS curves as the cage command control shape is the most practical way currently available for cases alike.

Using soft transform is also a real advantage if used carefully but it could be time consuming in complex cases and any change of plan may require a cycle of rework.

I just wish to be able to use multiple curves at a time, have non-destructive parameteres and faster performance.

Thank you mr. Zwart and anybody accompanied for your time and concern.
I hope to see this fix (2) and I hope to see an even more briliant Rhonoceroes 3D in the future as I’m pretty optimistic about it when thinking of the value of this concern.

Thanks! :slightly_smiling_face:

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