topic Re: ncloth nucleus scene scale in Maya Dynamics Forum

ncloth nucleus scene scale

alexkzy — Tue, 02 Jul 2019 03:15:15 GMT

Hi,

because I had problems with ncloth (my cloth is behaving very weirdly) I've searched through all internet for solutions. I know that you need to set your space scale according to your units. I'm modelling in centimeters so I have to set the space scale in my nucleus to 0.01 - I know that.

I imported the default ncloth example to my scene and loaded the silk preset to it -> It works, the animation looks normal. Then I set my flag to silk as well and copied all of the nucleus values to my nucleus -> it doesn't work. The only difference is that my flag is much bigger (x100 because I was modelling it in centimeters, a 200x100 cm flag) so I've set the nucleus space scale to 0.01 according to the relative size -> still doesn't work, my flag behaves completely different though it's setup is exactly the same as the working flag except the space scale.

I've even created a flag, doubled it, scaled the copy x100 and created a ncloth from each. Each ncloth got the silk preset and nothing further was done. I used the same nucleus for both with the default settings and just the wind attr set to 10 for seeing some effect -> The small flag behaves normally as you would expect, the big one is not moving. So I set the nucleus space scale to 0.01 and it is still behaving differently than the small one .. even when it's relativly identical. The difference is just the size and the space scale. The pinning is done by transform constraining two vertices each and identical values.

To make sure I've repeated this but this time I didn't scale the copied flag and didn't touch the space scale -> Both flags behave similar and normal!

I don't get it. What is the problem? Do you have to set more values than the space scale to adjust the nucleus properly? Or do you have to set something in other nodes? Could it be a bug where maya handles the scene scale wrong? Or are the properties in the dynamics nodes relative to a fixed scale and ignore what you set in the nucleus?

...

Re: ncloth nucleus scene scale

mspeer — Tue, 02 Jul 2019 03:53:26 GMT

Hi!

There can still be differences as dynamics are very complex, caused by different interacting attributes.

I recommend to leave Maya at default units ("cm") and use this as meter.

If you use other settings you may need to adapt values for multiple different attributes.

However i can't say for sure if this is a bug or not in case of nucleus / nDynamics.

At least, the problem is easy reproducible.

You can report this problem (bug?) to Autodesk here if you want.
In Maya main menu:
Help -> Speak Back -> Report a Problem

Re: ncloth nucleus scene scale

Anonymous — Wed, 17 Jul 2019 17:58:32 GMT

Lift is not compensated when changing space scale.

So multiply by the space scale. If you change it by 100 to make it 0.01.
lift default value of 0.5 becomes .0005

Re: ncloth nucleus scene scale

alexkzy — Fri, 19 Jul 2019 19:44:04 GMT

Thank you, that helped! Anyways, that makes life harder, because default value is set to 0.05 and multiplying it by 0.01 results in 0.0005, which is displayed as 0.001. The numbers are getting pretty small. Somewhat un-handy and I'd prefer to have it adjusted by nucleus internally if wished. (Or having something like an attribute scaling factor, which scales all attributes from a node for displaying, but that's probably overkill.) I played around with relationsships editor and other stuff but in the end, it's just to much work to do nothing more than scaling dynamic properties to make them work correctly. I mean, it's a linear relationship and should be solveable by just one factor in code ...

Also, I noticed that you need to adjust the wind speed value as well but it doesn't seem to be scaling with the scene as expected. In the centimeter case you would intuitivly multiply it by 1/space scale = 1/0.01 = 100. But the result is different. I had to multiply it by 10 to get in the 'similar' area. I thought wind speed is related to how many units wind travels in time, seems like I'm wrong or there is more to set again ...

Re: ncloth nucleus scene scale

Anonymous — Fri, 19 Jul 2019 21:23:02 GMT

Glad it helps.

Autodesk said they would not change it. To maintain backwards compatibility. 8(

You are correct about it being very inconvenient. You can change the channel box precision. But not the attribute editor.

I don't remember "needing" to adjustment wind speed but it's possible. Fields for sure need to be adjusted.