Collide attr and overall collisions clarification

[marcus]

Hey @magicleo88, welcome to the forums!

@magicleo88

Out of all the above, the only instance that seems to prevent the sim from breaking is when i switch the chest marker to “collide - off” and i’m not quite sure why and if there’s a better way to do it.

Then this definitely sounds like a self-collision issue.

Have a look at this method to visualise where there are contacts.

https://learn.ragdolldynamics.com/releases/2022.03.14/#contact-visualisation

I expect you’ll find some contacts happening inbetween markers in your character, that should give you some idea of which markers are indeed still overlapping.

@magicleo88

I was under the impression that when the overlap value is set to 0 for the same group elements (such as for clavicles generally), the intersection of those markers is overlooked and overlap allowed.

0 is a special value meaning “respect self-collision”. Meaning that if Self Collide = On then markers in the same group will collide with each other.

The exception to this, globally, everywhere, is markers that are direct neighbours to each other.

So if you’ve got two markers that do overlap - and you would like to permit this - then you’d give them another value. Anything 2 and above. I’ve found that 1 is another special value that isn’t working correctly, so 2 up to 65,000 or so is safe to use.

-1 is the final special value, meaning "collide with everything in the same group, even if Self Collide = False

@magicleo88

Additionally, how do groups play a part in collisions with other groups? Am i missing something there as well perhaps?

The rules are:

1. Neighbours may overlap
2. Markers in a group with Self Collide = Off may overlap
3. Markers with the same Overlap Group number may overlap, except -1, 0 and 1.

That’s about all the control you have here. If you have a scenario in mind that requires more control, then this is the place to let me know!

I do touch on overlap groups and self collision in the recent video just published here:

• https://forums2.ragdolldynamics.com/t/ragdoll-introduction-video/595

If this still doesn’t solve your case, feel free to upload your scene (or one like it) and I’d be happy to take a look. Just make sure it’s as small as you can possibly make it, 0-5 mb, and .zip it too, to keep our precious backups from exploding. Then you can just drag it into a post here.

PS: If you can make a mp4 instead of a gif, then that would help as we can scrub the video and get some idea of how long it is.