Working scale in Maya?

[Steve Davy]

I've recently been tasked with learning Golaem crowd sim software for work, and it's raised an interesting issue that's confused me for years.

I've always understood the "never change the working units in Maya" rule, and also always understood there was something funky about Maya's working units but never really got to the bottom of it until now.

So it seems that although Maya's default units show "centimeters", its dynamic systems are actually working in meters. So, one default grid unit in Maya is not one centimeter, but in fact one meter. This explains why all my dynamic sims over the years have always appeared to be running too slow.

However, most studios I have worked at -- and my own workflow for a long time too -- treat grid units in Maya as centimeters. This effectively means everything is in fact 100 times larger than it should be.

I am curious what other people's experience of this anomaly is -- do places you've worked at also great grid units as centimeters rather than meters? It does seem like most stock 3D assets come into Maya scaled as if this were the case. How do you deal with running dynamic sims in Maya?

Working with Golaem in Maya is made more difficult and troublesome by this weird legacy problem that I guess dates back to Maya's inception.

[Duncan Brinsmead]

The dynamics in Maya ignore the units settings. There are settings like space scale in different solvers where one can compensate for cm units. The main effect in almost all cases is just that gravity is 100x stronger. So alternately you could use gravity = 980.0 and leave space scale at 1.0. (note if your units setting was meters then you could just leave it at 9.8)

 

 

From: maya...@googlegroups.com <maya...@googlegroups.com> On Behalf Of Steve Davy
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Subject: [maya_he3d] Working scale in Maya?

 

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[Steve Davy]

I think in a lot of cases my solution for dynamics that look wrong has indeed been to hack the gravity...

The problem with Golaem is that it uses particles to drive its entire system, so understanding the scene units as they relate to dynamics is crucial. By default the Golaem system is set to meters, while of course Maya's are centimeters which is confusing right out of the gate.

And, their character pack entities are all scaled as if a grid unit in Maya is a meter, not a centimeter. It can get pretty confusing what your "absolute" scale is in Maya.

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From: 'Duncan Brinsmead' via maya_he3d <maya...@googlegroups.com>
Sent: Wednesday, July 5, 2023 11:27 AM
To: maya...@googlegroups.com <maya...@googlegroups.com>
Subject: [maya_he3d] RE: Working scale in Maya?

 

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[joiec...@gmail.com]

Glad you have the help of Duncan, it's great we have you here Mr.

In order to add to him, I confirm it is a very bad idea to change MAYA's units. Years ago I had to work with people coming from MAX and matched their world in meters, and God, everything messed up, starting with the grid settings and finishing with clipping planes settings for example!

[Nicolas Chaverou]

Late to the party :)

@Steve Davy feel free to use our support form for any feedback or questions

In order to add to him, I confirm it is a very bad idea to change MAYA's units.

I'll second that and this is why we advise to stick with the default Maya linear working units and the reason why we have our own unit system that you can change internally

It's set to meters as this is the actual default dynamics unit in Maya (take a 1 x 1 x 1 unit cube in maya and place it 1 unit above the ground turn it to a physics object and see how long it take to touch the ground and you'll notice Maya default dynamics unit is meters)

But it can be changed in the Crowd Manager node

their character pack entities are all scaled as if a grid unit in Maya is a meter, not a centimeter. It can get pretty confusing what your "absolute" scale is in Maya.

Our Character pack characters are also in meters as they have been modeled by french studios and those tend to work in meters :)

Sorry it sounds cumbersome but we haven't found a better way to deal with this and it's pretty similar to the other simulation based plugins in maya (realflow, yeti...)

Hope that helps

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