Matter-js: Disable collision between relatives bodies

[car1ot]

How to disable collision between relatives bodies? For example, I have a lot of balls, they fall and collide by walls, but they should not collide with themselves. Please someone explain how to make it?

[michael-garofalo]

It looks like you're looking for "Collision Filtering"...

https://brm.io/matter-js/demo/#collisionFiltering
https://github.com/liabru/matter-js/blob/master/examples/collisionFiltering.js

I haven't tried it. But if I'm understanding this correctly, it looks like you'd create a "walls" category, then set a "collisionFilter" on the balls, where the mask would be the "walls".

[car1ot]

It looks like you're looking for "Collision Filtering"...

https://brm.io/matter-js/demo/#collisionFiltering
https://github.com/liabru/matter-js/blob/master/examples/collisionFiltering.js

I haven't tried it. But if I'm understanding this correctly, it looks like you'd create a "walls" category, then set a "collisionFilter" on the balls, where the mask would be the "walls".

No, it not works for me. Because relatives bodies collide between themselves, cause they gonna have the same mask.

[michael-garofalo]

Well, how many balls are there? If it's 30 or less, why not create a group for each ball, one for walls and one general group?

[liabru]

I think you could set the balls all to have a negative group e.g. -1 and the walls a positive group (default is 0 so that's fine).

Would that work? You can combine these with masks too. If you need something really custom, you could patch Detector.canCollide with your own logic.