Allow Unions To Stretch

As a Roblox developer, it is currently impossible to stretch a union’s dimensions, as you would an imported mesh, they can only be scaled proportionally. (e.g. can be made twice as tall, wide, and deep, but can’t be made twice as tall while maintaining the same width and depth)

An upcoming update to Innovation Arctic Base allows players to replace limbs with robotics ones, made out of unions. If the CharacterDepth/Height/Width scales are changed, the limb will not stretch to reflect this like the other parts of the character do, as unions cannot stretch.

Limb will not resize correctly unless BodyDepth, Width, and Height are changed by an equal amount

(Test Limb Only - may cause injury, death, or explosions if used as an actual leg)


Probably impossible. Spheres (the Ball PartType, not the mesh) must scale uniformly in all directions. If you were to create a union which uses a sphere, scaled it non-uniformly, and separated it, what would happen? Is that information just lost?

Just export it as a mesh and re-import it.


Unions can’t – and I think will never be allowed to – scale non-uniformly because there’s not really any good way for that to interact with separation. If you scale a union in such a way that skews the parts it’s made of and then separate it, what should happen?

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A rather simple solution would be for the csg system to automatically detect this, inform the developer and resize the union accordingly, should he wish to proceed, to a size that is proportional to the size of the original Union before finally seperating it.
This would be preferable to not having the option to resize Unions at all atleast.


I agree, this is a way that they can get it to work perfectly. After stretching the union to its final form, I usualy do not intend to do anymore operations with it


Hi all, this is a very old post but the issue actually still exists. As we are working on the new CSG engine - Studio Beta: CSG Has a New Engine - Vroom, Vroom, Vroom! - this is definitely something that we are looking to improve.
There are a few options we could consider:

  • Ignoring or changing the scaling when we separate a non-uniformly scaled union - with potential user warning -
  • Allowing the direct conversion from Union to a mesh. You can then scale any way you want but you lose the ability to separate.

I will start that conversation in our team and I will update you if and when we have a clear decision. In the meantime, don’t hesitate to give me any feedback on that particular issue or on anything CSG related.