Deprecating Legacy CSG System

I haven’t noticed any change in my game, why is that?

I have the announcement in my place, yet the colours on my unions are still there.


I preferred CSGv1 over CSGv2 because it makes the types of creations I make more smoother (I build things with spheres), and it was quicker for me.
When I used CSGv2, it makes my modeling process a lot slower, and it makes my stuff look incredibly bad, most of the time.
Why not just leave CSGv1 as it is, and not remove it? It’s honestly sad to see CSGv1 go, I think i’ll have to move to Blender from now on.
Edit: And as people have said, CSGv2 has a tendency to corrupt unions. I know this from experience using CSGv2. Please. Keep CSGv1.


Well you could always use something like trenchbroom, it’s kind of like unitys probuilder but on tons of steroids :slight_smile: You can export meshes as obj and you have some csg features like roblox has like subtract/carve, hollow, intersect, etc (its union support is pretty limited though because of how TB works), it also handles UV mapping automatically for you which is nice too, if you want to make low poly type maps I would definitely recommend it though if you want to make maps with tons of fine detail or organic terrain I would recommend blender


Shouldn’t you be advocating for CSGv2 to be improved instead of insisting we keep 2 CSG systems?

Meshes don’t have a real-time API for construction/destruction/geometry modification :wink: They’re still useful


Instead of using negative parts and all that, why not use vertices?


Please- add this with that because it will stop our CREATIVITY


Only issue I have with this is that unioned cylinders are either rotated differently or have have a completely new geometry. To fix this issue, I switch to the legacy CSG system and union from there.

To reproduce, just negate a part, union it with a cylinder, and then look at the side geometry. If this could be fixed/improved, the system would become perfect for my needs.


Please do not remove CSGv1. CSGv2 suffers from several issues that I have encountered over the time I’ve modeled on this platform, offsetting issues, the lack of being able to “bake” color onto surfaces with negates, and many more. While I don’t know how many of these issues are fixed from when I last actively used it, I know that CSGv2 doesn’t work entirely well with CSGv1 unions that I have relied upon for years. I have models that I still update to this day going back years that were built on CSGv1.

For those that will suggest the argument of: “Blender can do what CSG does better.”, yes, that is true. Blender is one of the most capable software for modeling and animation right now, but Roblox seems to be stuck in a place between wanting to be a professional game development engine or something that amateurs can pick up quickly and learn. I doubt that most children who use studio would want to pick up a whole other software, and would probably opt to use CSG instead. Ideally when I work on Roblox, I want to do as much as I can inside the program itself, the option of being able to use external programs is nice, but in-engine tools for modeling are just as important, especially for novices.

Up until this point and even then, CSG has received little support besides SmoothingAngles and the release of CSGv2. The removal of CSGv1 baffles me really, as I know many modelers who’ve came to rely on it even after it degraded over time, disappearing unions, all that.

I feel like this is in some way apart of a larger problem that I mentioned earlier. Roblox has to decide whether it’s for professional developers who work with multiple programs or to be a platform that amateurs can easily pick up. It’s possible to be both, but to be both, you’d have to sacrifice a lot of both sides.


I guess if the new system is near 100% backwards compatible with V1 and is more efficient, I’ll switch to that. But I’m sticking with CSGv1 as long as I can, even using older builds of studio if I have to.


I don’t use CSG V1, but honestly I am very disappointed in this.
You need to add the option to use color negative parts to color faces of objects.


CSGV1 builds are always much more mesmerizing than CSGV2 builds.


What about color negating?
Is that still a thing?


Wait, please help me understand. We won’t be able to create unions in studio anymore? Is this being replaced? I’ve been a bit overly dependent on NegativeParts in my scene building, so I’d like to know if I need to start experimenting with alternatives.


For context, I have been using CSG V2 and CSG V1 interchangeably for a few years now. I am very familiar with the general strengths and weaknesses of both systems.

  • In a nutshell, CSG V1 has a lot easier of a time with wedges and bricks, due to CSG V2s much higher tendency to create micro-gaps.

  • CSG V1 has higher accuracy when it comes to unioning spheres and cylinders, it has always annoyed me that CSG V2 simplified these shapes, and I’d like to see a “high precision” mode that fixes this issue. Or just… Leave CSG V1 hidden in some random options section. See: Repro.rbxl (43.6 KB)

  • CSG V2 takes a long time compared to CSG V1, ESPECIALLY with spheres, My guess was always that this was because CSG V2 is rebuilding the entire tree.

  • CSG V1 also tends to have smoother shading, this could be completely remedied by being able to choose smooth or flat shading, and having an edge split tool like in blender. The SmoothingAngle property is sort of janky right now.

  • As noted by many others already, CSG V1 allows you to color individual faces of unions via negations. This unreplicated behavior could be turned into a “face coloring” tool, which would be a lot more useful and intuitive.


Last time I used CSG 2.0 (around January), it was completely broken. I would save/re-load a place and half of the CSG’s would still be rendering physics but not actually be on the screen. Trying to separate the union would crash the session or just delete both. The only fix was to revert to the legacy system.

I hope there have been updates since then. I know I was not the only one experiencing this issue at the time.


@meshadapt Could the CSG system continue to be used in the future or it is just an update/improvement?

EDIT: I never used old CSG system, snice i dont have it enabled on settings…

If you delete CSG system you will ruin me, yes, i use CSG a lot, CSG is my life lol


No its the system is what’s being replaced for what should be a better one. Unions will still exist.


As you never used old CSG system, you can ignore this announcement. You are able to use CSG system the same as before now and in the future.


As long as disappearing issue is fixed with v2 Im happy with this update, else ill be pretty annoyed


@Zeezy2204 and @ Naco88
This does not affect models in-game that were made using CSG v1.

All CSGv1 made models (or old unions) will appear exactly the same in game and in Roblox Studio.

If you perform in-game CSG operations using old unions, the results will also exactly the same because only the new system supports in-game CSG.

If you perform CSG operations in Studio using old unions, old unions will be automatically regenerated using the new system.