MASH Dynamics collision object

[fatjulio]

I'm trying to make a poly object collide with a MASH setup, like a sphere going through a grid of cubes, as in the basic demo. It works in Maya 2022, but not in Maya 2023. In Maya 2023 (and 2023.1) it seems to only take the collision shape on the first frame, ignoring it's animation.

[sepu6]

It works fine for me in 2023.1 and 2023 Here is an example. 

The key is to change the animated collision shape to "Mesh" 

 

 

[fatjulio]

Thanks for the reply. I deleted the preferences, and that helped. My situation has a container holding a lot of objects, and the container moves. It sort of worked, but leaked a lot once the container moved. I increased the internal frame rate, but it still leaks. I don't think Bullet physics handles this situation well.

Would there be another dynamics system in Maya to try? There are 2 different types of objects in the container, and over a 1000 copies in total.

[sepu6]

what kind of objects? can you share your setup? 

You could try ncloth as well 

[fatjulio]

Here's my scene.

[sepu6]

I had a look at your scene today, busy with work, anyways. Yeah, bullet can def have issues with this kind of simulations. Is not an issue of the geo coming down and colliding but the quick animation that you have on the collision can def cause issues, also the bullet implementation isn't great in Maya. 

So for this, I think MPM is the way to go and it works quite alright as you can see. Since MPM is multi solver you can use it for more than this, for example, you could create a quick grain sim on the yogurt so your pieces can interact with the hard pieces, etc.  MPM is not as fast as bullet but is way more accurate, and is getting improved with each release, so I would highly recommend using BF 2.5. This took 20 mins on my machine and you could go a little higher on the resolution of the sim if you want a more accurate collision of the pieces. 

I did a two-step process first creating a grid and simulating that so the pieces fall and create a rest position. Then run another sim for the final pieces. 

First 

I ran the first sim so the pieces settle on the collision and move the cluster animation to frame 12 and muted the animation keys. I drop a file cache and I ran it for 55 frames (you can do more or fewer frames, is up to you).  this took 5 - 8 min. 

 

 

Then I created an initial state for the sim and I loaded the last frame save from the first sim, so it starts on the rest position that I want. Unmute the animation of the cluster, disconnected the source_mpm_shell, created another file_cache node to save for the final, and run the sim again with a drag influence to slow down the pieces each time step. 

 

This is the whole network

 

Hopefully, this helps, Cheers.

[fatjulio]

Thank you, I'll check it out.

[fatjulio]

I've downloaded your file and updated Bifrost to 2.5. The quick grid node isn't working. It's red and says it has an unknown node definition.

I've made an object as the point input to plug into the network, so I have points now.

[sepu6]

The quick grid is coming from here. Jason Compounds which I highly recommend installing 

https://github.com/unkaval/VHH