Cloth FAQ

Cloth FAQ

Where to find the Physics DCC plugin to create Apex files?

To be able to create Apex files, you will need to install the Nvidia Physx DCC plugin. The plugin for various Maya versions can be found here and is now maintained by Golaem. Please get in touch with our support if your Maya version is not listed here. Notice that within Linux, you may have various errors when the plugin is loaded / unloaded in Maya: this is expected and does not have any impact on the cloth configuration.

Notice: in order to install the Physx plugin, you need to set one environment variable for Windows (MAYA_MODULE_PATH) and two for Linux (MAYA_MODULE_PATH and LD_LIBRARY_PATH) as below:

  • MAYA_MODULE_PATH=[PhysxPluginDir]
  • LD_LIBRARY_PATH=[PhysxPluginDir]/ContentCore:[PhysxPluginDir]/ContentCore/PhysX_3.X:${LD_LIBRARY_PATH}

Some errors pop when loading the Physx For Maya Plugin under Linux

When loading / unloading the Physx For Maya plugin under Linux, you may end up with cryptic error messages in the Script Editor such as

// Error: ...source "/apps/Linux.x86_64/physX-3.4/PhysXForMaya2020/plug-ins/libphysx.so/????????????????????????????????????? // // Error: Line 1.170: Syntax error //

Noticed that those errors can be ignored and do not have any incidence on the plugin usage

Golaem clothes have a high frequency vibration

This happen when a simulated cloth has interactions with a golaem character or a Crowd Rigid Body in kinematic mode that are simulated at a different frequency.

By default, the physX simulation in the golaem Physics Locator uses 3 substeps, which means that for every frame played by Maya and simulated by Golaem, the physX makes 2 additional updates. But when there are interactions between Maya / Golaem and the physics, this can produce high frequency vibrations.

To remove them, the Physics Substeps attribute in the the Golaem Physics Locator needs to be set to 1.
If the physics becomes unstable and there is no Crowd Rigid Bodies, then the Substeps in the Crowd Manager Node can be increased. If there are collisions with some Crowd Rigid Bodies in Kinematic mode, then the Substeps in the Crowd Manager Node has to be let to 1, but the framerate for Maya itself can be increased to stabilize the whole simulation.

Export Selection as apx file doesn't work in Maya 2022

Exporting a cloth mesh as an apx file using the Export Selection menu of the PhysX plugin in Maya 2022, results in an invalid apx file (does not contain any cloth mesh) or it's missing. This is a known issue with Maya 2022, the workaround is to use Export All.

Apex only supports 4 bones per weight

Due to hardware limitations, Apex only supports up to 4 bone skinning influences per vertex for its cloth deformation. If more than 4 influences are used in your model, you usually get the following warning message when creating a Apex Cloth within the PhysX plugin:

// Warning: Some vertex use 6 bones for weight (|pPlane1|pPlaneShape1). PhysX only supports 4 at most.

Notice that, this warning does not prevent to save the apx file and use it within Golaem but keep in mind it will only recall the 4 biggest weighting influences when cloth simulation will be computed. This does not affect the vertices which are not cloth simulated.

When I export the cloth as apx file an error message says "non orthogonal bind pose".
It usually means that one of your bone has a scale on it. Please check if it's the case.

Here is the mel script to make sure no scale is applied on any bone:

string $joints[] = `ls -type "joint" -long`;
print $joints[0]; //the first joint
* loop through all objects */
string $joint;
for ( $joint in $joints ) {
setAttr ($joint + ".scaleX") 1;
setAttr ($joint + ".scaleY") 1;
setAttr ($joint + ".scaleZ") 1;
};