MASH Time node and Dynamics not evaluating?

[a.mayaUser]

Hi guys,

it looks like that the MASH dynamic node takes over the Time node in a way that the objects looses their own animation.

I don't see anything about this in the documentation, so I don't know if I'm making something wrong or it's a known limitation or incompatibility.

Also, any idea how to solve this?

[sepu6]

you have to play with the Mash bias options on the Maya dynamic node.

[a.mayaUser]

Thanks @sepu6 maybe I should give more details and explain it better:

let's say I have an animated deforming mesh, maybe with a non linear deformer, like a bend, or maybe a basic rig or anything else that can reshape the geometry. so if I create a simple MASH stack like distribute->time, the animation play regularly and I can do everything etc.

The moment I add the dynamic node, MASH adds the dynamics to the objects, and yes, they fall and bounce, but the deformation is not taken into account.

The result is that the collisions do not work properly because they are evaluated on a static mesh instead or - I guess - only on the shape resulting on the first frame of the animation.

The problem is visible using the debugging tool in the MASH bullet solver -> collision shapes flag ON. The shape doesn't update like, indeed, it is not deforming.

I also tried changing the collision shape to mesh, instead of automatic, in the dynamics node, without success.

I hope this helps to understand the problem.

[sepu6]

Yeah, you need to tell the solver to update each timestep if not it just gets the first frame. As far as I know, you can tell the solver to update the collision shape each timestep unless you change the shape to mesh, not the dynamic node. I would like to see what is the end goal. if you are dropping stuff into a character which is Mash as well you can have a second Mash network and the solver will work since it uses the same one. 

If you have animation done with Mash you have to up the bias options for the mash animation to take over.  I know what you mean but maybe there is a different way, so if you have an example of what you are trying to accomplish would be best to help. Cheers. 

[a.mayaUser]

Okay, here's a quick videos of a super basic nonlinear deformation using just the Time and the Dynamics nodes, but again, it could be something else, like a basic 3 joints rig or a completely different deformation done in the shape node.

One video is with collision shape set to automatic, the other one is set to mesh. I can't find the way to tell the solver to update each frame through a timestep setting anywhere in the nodes though. Also, the limit with the bias node is that it doesn't take into account the deformations, but only the position and rotation of the whole thing, unless there is another bias settings I'm missing somewhere else.

At this point I'm just doing experimentation because I need to prototype some ideas and see how I can approach them in MASH and I could be wrong, but I have the suspect that can't be done entirely in MASH, and I need a different approach using nCloth, or a combination of both nCloth and MASH, but still not sure how.

[sepu6]

Yeah, I do not think Mash can do that. So you probably gonna have to do a combination of ncloth + Mash as you mentioned. 

[a.mayaUser]

It looks like the solver is capable of evaluate a changing mesh using, for example, the random node on the scale settings. It doesn't though if the deformation is coming outside MASH like in this case.

That's very unfortunate that MASH development is abandoned, it's still one of the fastest and best integrated tool in Maya for a lot of stuff.