Deprecating Legacy CSG System

Will this effect models in-game that were made using CSG V1?

Just double checking as I have a game that relies on it completely.


The “Learn More” button redirects to a private topic:

I think it’s because it has /draft- in the URL, it’s a draft, not a post.


This, by far, will be one of the hardest updates for me to swallow.

CSG v1 has always been my go to version for modelling smooth objects (such as airplanes), as it didn’t have the sharp affect CSG v2 has. Even with the CSG v2 smoothing angle, I couldn’t get any of my unions to be as smooth, while retaining the shape I want.

I also loved having the ability to have the face of the part that was unioned to be the color of the negated part. This made it simple to add some colors, without having to add more parts/unions and hope that they didn’t corrupt.

In my experience, CSG v2 would always corrupt when I tried to model a plane. This would make me save hundreds of unions in the file, so in case one corrupted, I could try to recover it. CSG v2 never gave me a too complex/too large warning to tell me to stop, unlike CSG v1.

This is also concerning for when I would do “paint jobs” on planes, and I would union with CSG v1 to keep the plane smooth and not with any new creases. CSG v2 would always add new creases to the plane, and make it look horrible, like a crumpled up paper airplane.

Is there any way we can keep CSG v1, and use it? Possibly make a plugin that allows you to still use CSG v1? As I would not like to see this change occur. If there isn’t, I guess this update means I’ll have to learn Blender, and import all my meshes into Roblox now, since CSG v1 is getting removed.


Yep, It’s going to be hard to make CSG aircraft now… Probably just going to switch to mesh but I’d love if Roblox could work on something to fix it…


Would hope not, considering CSGv1 objects are already hosted via the Roblox website on a technical level - I see no harm in keeping these up, and turning off the creation of new ones.


What I struggle to understand is why Roblox is still investing in CSG. The tools are lacklustre and cannot be compared to better solutions like Blender. At any moment your unions could just magically disappear without a trace (the fact that someone had to write this post proves why I will never touch CSG).

The time you spend trying to cobble primitives together with CSG (which half the time errors when you try to use it) on a project could have you become proficient enough in Blender that you are already pumping out far better quality models than any user of CSG can ever dream of. Using Blender gives you security in that your models won’t magically vanish, gives you far more control, and your skills in it can be applied outside Roblox and used in the future.

Instead of Roblox trying to reinvent the wheel (like usual) and compete with leading tools, why not create better integration for those tools? Maybe provide better documentation and tutorials on how you use them so that even new developers can easily grasp it.


Oh my god… I am going to actually have to change negate colors now. This is a bruh moment.


I need a way to keep the colours aswell, its a must need for my rocket engines and i have no idea how to create them with a different method.


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?