Introducing Intersection to Computational Solid Geometry (CSG)

I’ve tested this and saw things looked fine. I should definitely try exporting a mesh I’ve made and see what Roblox does to it. But it does bring up the concern of if that’s how Roblox sees the mesh with the extra geometry? Triangles are obviously part of making a mesh, but this is more in regards to things like a vertex overlapping the same point creating more triangles. I know for a fact that a proper geometry solver wouldn’t be too far out of reality where the mesh can be properly quadded (basically a grid of normals that make up the shape without N-gons or pure triangles). I would like to see the actual result of making a union opposed to using Blender which might not be the proper way considering the possibility of the exporting process being funked.

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Yeah the exporting system is very annoying and really needs to be worked on especially if the game engine sees it differently. Hopefully we can see improvements to this system in the future so we can better compare unions to custom meshes.

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why was grid increment also changed in this update? I can no longer build at 0.0125 in increment when scaling or moving parts, as roblox prevents it and changes it to 0.013.

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What is the keyboard shortcut for this?

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Oh yes!!! This is lovely. Will be using asap!

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Finally!

Glad to see this feature is now a thing.

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Really cool update! Only issue i found was that my studio crashed when i used Ctrl + Z to undo my intersection

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Looks good! In what purpose can we actually use it?

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Ok but like why are unions still unbelievably broken when it comes to nightmare topology and active geometry calculations?

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I’ve wondered for so long now why this wasn’t a thing on Roblox, glad to see it implemented!

Why not switch Unions with Meshpart in roblox studio? due to MeshParts have more options to optimize it more than the Unions

You can change the collosion mesh quality via TriangleMeshPart.CollisionFidelity

Responses to questions:

@SomeFedoraGuy

What is the keyboard shortcut for this?

Thanks for the reminder! The keyboard shortcut is: Ctrl + Shift + I .
I updated the original post as well

@Veldaren

Glad to see this feature is now a thing.

Thanks for the link to the previous request, I responded to that so that everyone on that thread is aware that Intersect is now a supported CSG operation.

@iGottic

Ok but like why are unions still unbelievably broken when it comes to nightmare topology and active geometry calculations?

Would love to hear more details on what specifically is broken. If you have example place files or models you can share, that will help us track down any specific issues

@PablitoTheChicken

Really cool update! Only issue i found was that my studio crashed when i used Ctrl + Z to undo my intersection

Hmm… interesting we have been trying to reproduce this but have not been able to. Any more info you can provide about what might have been going on previously? Or the scenario you were working with? If you have a model / place file you can share the specifically reproduces this, that would be super helpful too

@Verystupid_stickman

why was grid increment also changed in this update? I can no longer build at 0.0125 in increment when scaling or moving parts, as roblox prevents it and changes it to 0.013.

This is an issue that is not related to Intersection. We have passed this info along to the team responsible and they are taking a look it. Thanks for reporting!

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So far my favourite thing about this is the time saving
Gone are the days of having to duplicate negative parts n stuff

Great feature to be added to CSG,
but I unfortunately ran into an issue using it, sometimes it creates thin layers When negated Intersected part union with parts:
Negated Intersected Part(size:5, 2.5, 2.5):
Screenshot 2023-04-08 001330
Regular part(size:5, 2.5, 2.5):
Screenshot 2023-04-08 001429
Unionized:
Screenshot 2023-04-08 001513

@syntezoid just reached out to me and I sent a response a few hours ago!

Damn. finally roblox getting their priorities this is so cool

This is definitely a step in the right direction! Roblox is finally adding useful features to studio again!

The negative part probably means it does the opposite of intersect

Use a regular part instead

At least with my testing, I’ve only ever found issues with unions in regards to collision physics. If you weld everything to a custom simple hitbox, it appears to fix it. Though I will agree that this shouldn’t be necessary ideally.

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