Unioning changes the part colours of some faces? MAJOR BUG WITH CSG

You can’t do that because still it won’t be the perfect color to match the part. Also, the (unioned part) material will/might have some reflection.

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I can change face color and materials work fine. I can also MATCH face color.

@achqes turns out the solution is to set smoothingangle to 1 and then to 0. it fixes the weird shading + doesn’t break if you set it back to 0

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A few things have changed since this post was made:

CSG V3 is now fully released, and is not a beta feature.
Enabling legacy CSG does not enable CSG V2, it actually enables CSG V1.

Separating old CSG V2 unions retroactively applies the negative part colours to the union even for steps before the current union separation, which makes improving old models extremely tedious.

CSG V3 negative parts also darken the faces they have touched, for no reason at all :confused:

Roblox staff have ignored my requests to add a toggle to turn on and off the face colour changing. I would appreciate it if others could also politely request for Roblox staff to try and get this feature implemeneted as it would greatly improve modelling for many developers, especially for reworking older models where instead of separating to the point where you have the part you need to modify, you need to COMPLETELY separate the model to then apply the right colour to the negative parts, or even split negative parts into different parts just to apply a livery.

Also, PLEASE call on Roblox Staff to FIX the bug with CSG V3 where negative parts make faces randomly reflective or neon, it is literally making it impossible to model.


enable the usepartcolour property for the negative part, by default it is disabled
Properties > Data > UsePartColour > enable (:white_check_mark:)

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CSG V3 is very functional and definitely has no bugs at all!

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UsePartColour is enabled.
Some faces are still grey

CSG V3 is broken and it does this all the time, however you can fix the majority of faces by using smoothing angle. You can turn smoothing angle back to 0 if you wish to not have it alter the model angles.


even with smoothing angle some faces may be distorted beyond repair.

Sorry for the recent glitches in CSG V3. Would you please reboot your studio and see if gray faces go away? Thanks!

This is a bug with the rendering of unions, and thus will not change unless the union is re-rendered.
Unless a fix to this bug has been made, recalculating the union will not make a change, apart from randomise the positon of the distortions on the broken faces.

Edit: I have recalculated the union and the bug infact seems to have been fixed! Please pass on my thanks to the developers responsible for fixing CSG V3.

Not gonna lie, thought this was a feature this entire time and have been abusing it in some of my builds since I can attach multiple colors to one part without having to use a new wall, lol

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you thought faces being distorted was a feature…?

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