Non-Uniform Union Scaling Beta

Unfortunately the ship has sailed on primitive cylinders scaling correctly: We would break way too much existing content out there if we changed them to having scaling that matches the bounding box.

For spheres it would be possible, but have some costs: The cost of physics for a stretched sphere is more than an order of magnitude higher than for a primitive round sphere, so making it easy to stretch spheres could cause some builders to accidentally work themselves into performance issues. On top of being inconsistent with the cylinder behavior since we can’t change that.

As you note, there’s at least now a “native” way to do it without having to resort to the deprecated SpecialMesh Instance.


Is this actually enabled? I’m trying to scale an union but it keeps scaling it uniformly :derp:

This doesn’t seem to work very well with materials. The material just stretches. (2022 Materials)


The beta feature is enabled, but you still have to choose to turn it on, have you?


Yes, I have the beta feature enabled but the Union is still being scaled uniformly instead of stretching


I thought I had the material handling working correctly but it turns out I didn’t look closely enough, I’ll get a fix in for this!


Amazing! We really needed something like this. It’s no longer painful to resize unions!

1 Like

I literally thought an update like this was an impossible pipe dream. This is incredible. I love this. This is absolutely going to change the way I model forever, and I’m very, very excited to use it. Thank you!

As for rollout, I’m leaning toward option 2 for simplicity’s sake. I imagine there’s not many use cases of letterbox-stretched unions. If there are, they can be fixed, most likely.

1 Like

It’s an amazing function Thank you.
I’ll test it now
((I have a wish… I wish I could change the color of the union))

I have it enabled, but its not working for me.

Have you ever restarted Roblox Studio? I restarted the studio and it worked

1 Like

Yes, but the second attempt apparently got it working lol.

A little small issue here. As I unioned the part with NegativePart in middle. The unioned part doesn’t scale properly like BasePart. Was this feature supposed to work?

Never mind! I have to restart my studio and it seems to be working again for me. A great feature to exist!

1 Like

What if a union is letterboxed pre-update? Will it keep being letterboxed after the update? If not, I fear that could create some backwards compatibility issues.

1 Like

You already can! Just enable the “UsePartColor” property of the resulting union.

Currently the beta is changing the existing letterboxed unions. Our analytics suggest that the number of existing letterboxed unions is low enough number that we might be able to just change them, but high enough that we’re not decided yet, please let us know whether you run into issues.


This already came in handy, i made this white lining in the wrong proportions, i’m now able to resize the union closer to where it needed to be.
And you may be thinking, you must be crazy for making that out of parts…
yes, yes i am.


Cool! I think we could get this thing earlier, because this can be usefull.

epik!!! this will really help with making my cars


Finally! No more manually exporting and them reimporting unions to scale them with mesh behaviours. This will be really useful. Nice work.


Been noticing these material distortions when scaling, not sure if this is possible to fix this happening when scaling (although you can just separate and union it again), but overall, this feature is a great QoL.