Here comes SuperCammy
The following is all I know about authoring Apex cloth with the standalone tool (that is to say : not using the Max or Maya plugins) :
- The tool is called "ClothingToolCHECKED.exe", part of the Nvidia Physx tools. I've only used the 32bit version as per a suggestion I saw online - I have no idea if the 64bit version actually works (it probably has bugs ?).
- Since Apex cloth is tied to material slots, there are a few weird things about the system. For instance, the main character FBX (used for the main import in UE) might or might not need to have the cloth polygons in it (I am getting conflicting results on my tests about this - I feel like the cloth bits do not necessarily have be in the main FBX, but the non-cloth bits seem to be required in the sim FBX. It's weird !). However one thing is certain : you need to make sure that the main model has at least some polygons assigned to the material eventually linked to the cloth sim file, because if not it the required material slot won't show up in UE on import in the first place.
- Steps to generate cloth sim in the standalone tool :
1 - Import the FBX used for sim (not your whole character - only the parts that match the material slot you will dedicate to Apex simulation in UE.)
2 - Painting max distance values (that tells how far each vert can travel, about 1.0 meter max for a cape/trench coat). Right-click erases. Set the max value to 1, scale to 1, and then put the paint slider to the strength you want to paint (here I used 1.0 at the bottom of a cape, and 0.1 at the shoulders). Once done click smooth once to smooth everything nicely.
3 - Painting slave latching. This tells which inner verts are going to be driven by outer verts, thus avoiding interpenetration. Make sure that you paint slave latching all the way to the edge of the fabric, if not it will flip on itself during sim.
4 - Running a first test sim to see if everything is fine, adjusting fabric properties if needed
5 - Save your workspace !
6 - Working on collision volumes. This is tricky, and a bit buggy. I've only been able to generate volumes based on bones initially present in the weighting of the model, meaning that even though a cape is not supposed to be weighted to an arm, I had to make sure that at least some verts were weighted to that bone ; if not, the program seemed to refuse to generate collision from these bones, even though they show up in the armature tree. And in order for collision volumes to show up at a predictable location I had to include thin polygon strips coming from, say, the surface of the arms and legs. Not necessary, but it saves me some time when it comes to positioning collision capsules.
7 - Tweaking fabric properties
8 - Generating a final sim, calculating tangents, generating the cloth mesh, saving the asset. This creates the .apx file for UE
I am getting an odd UV/material issue on Cammy's leotard here, probably an oversight on my end at some point in the process. It is probably not relevant to sim anyways but that might need to be double-checked.
That's about it !