Pre-deformed CageEdit


We are trying to apply the same cage edit to different geometry at different moments in our work, so naturally we wanted to create a cage, deform it, and the be able to apply it to our models.

We have some wierd skewing going on, so I dug around in the forum and found this old topic :
Custom Cage edit - Rhino - McNeel Forum

It references a youtrack issue “Pre-deformed cages do not work” but the link is dead.

Is this a known bug, normal behavior or some other thing?

I joined a 3dm to illustrate.

launch the CageEdit command
Select the black box as captive object
Select the white cage as control object

Version 8 SR4
(8.4.24044.15001, 2024-02-13)

CageEditSkew.3dm (188.7 KB)

Thank you.

Hello- that is the expected - well, expected by how the thing works currently - - the object is deformed from xyz space to the cage’s space.
Why do you want to reuse this deformed cage? What would the result be if it worked as you like?


Thank you Pascal.

Like I said, We’d like to use the same squishy-skoosh transform on many models. Currently we have to store an empty cage as reference, and the use the new cage created with CageEdit>BoundingBox and move all the points manually to the reference cage.

Apparently cage objects are not yet accessible from Rhinocommon so it’s all by hand.

I would ideally expect the same result as when creating the cage from the CageEdit command.

I can understand why it would not be exactly the same, but I don’t understand where the skewing occurs when I only moved the cage control points in the ZX plane.

When you say xyz space, I assume you mean World XYZ, and that a custom CPlane wouldn’t change anything?

Hello- what happens is the cage as is, is applied to the object - there is no constraint that says the cage must contain the object as a bounding box, which is where I think your expectations are coming from - I do not know if there could be but there isn’t, so the object is not jammed into a deformed bounding box.


Yes I understand that. My surprise is the skewing in the XY plane. I really don’t understand where it’s comming from if I only move points in ZX.

Any edit once a pre-deformed cage is applied will zoot the captive into whatever configuration it would have if it had started from an ortho cage. (for instance just move the cage object) I would prefer this to happen as soon as the deformed cage is applied, then it would not seem as though the first edit goes haywire.


Sorry, I didn’t understand that at all!

Maybe with this file you will better understand what perplexes me.

Or in other words, what good does the Cage command do? It feels like CageEdit is the only useful tool.

CageEditSkew2.3dm (2.6 MB)

I confess the What?? one I do not quite get either… I’ll stick it on the bug tracker. But … these are not the same as the one you posted originally where the object was larger than the cage being applied.

Cage can be useful in creating a cage that overlaps an object and the edit type is local. But yes, I would agree it is probably not often used. Nevertheless, thanks for these examples, at liast a couple of them look wrong to me.

RH-81295 CageEdit to deformed cage


Status is Won’t fix :sob:
At this point I can only hope cages will get more support in RhinoCommon (RH-21498).
Thank you for your time anyway.