topic Re: XGEN: map to ptex very slow in Maya Forum

XGEN: map to ptex very slow

Anonymous — Mon, 11 Jul 2016 13:12:46 GMT

I've been using XGen to great success so far, thanks

However I'm having issues with the speed converting my 3d paint maps to ptex (using the standard XGen controls).

Its incredibly slow, about 10 minutes every time I try and save a single map. This makes is basically unusable.

The scene is very responsive, even refreshing the groom. My issue is with the conversion time.

Scene setup:

3 poly surfaces as base (2000 quad each)

Total scene instances are 10,000

ptex map resolution under 30

18 archive files

hardware:

hp xeon 12-core workstation, 64gb ram

Are there any tips I should know about for my setup?

thanks

Re: XGEN: map to ptex very slow

Michael_Todd — Mon, 11 Jul 2016 22:55:12 GMT

Do the meshes that XGen is bound to have a very large surface area? The only reason it should be taking that long is if the maps are very large as the texel resolution is defined as texels per unit area. As 30 tpu is a very reasonable resolution, the surface area of the meshes could be a factor. XGen uses cm as the base unit internally, regardless of the Maya unit setting, so if you are using Meters as a unit, the ptex maps could have a very large surface area to cover and the 30 tpu resolution could actually be a lot higher than needed.

IF you are set to meters, obviously

Cheers

Re: XGEN: map to ptex very slow

Anonymous — Tue, 12 Jul 2016 13:35:46 GMT

Thanks, I did some profiling today trying different tpu resolutions.

It make a huge difference to the save times! Down to seconds from many minutes.

5tpu resolution seems entirely reasonable to work with in my scene.

I was using cm, but pre-scaling my terrain down to give better control of the density, so my original calculated mesh was only a few cm large.

Huge help, thanks!!

Re: XGEN: map to ptex very slow

Michael_Todd — Tue, 12 Jul 2016 14:55:55 GMT

Cool.

One thing to to note is that XGen creates a pref for the geo in it's un-deformed/un-translated 'Bind Pose' so it may have been using the original scale for it's surface area calculation. You could make a copy of the geo at the larger scale, scale the original down, freeze transforms then use a blend shape to the copy to size it back up, then the pref will be calculated at the small size. This will affect density, though, as Density is calculated as primitives per unit area..

Cheers

Re: XGEN: map to ptex very slow

Anonymous — Mon, 18 Jul 2016 15:52:27 GMT

I noticed this bind pose scale attribute is added to the mesh / shape when it's first added to the description.

I've been using this to query and delete the attribute during setup, in order to get the density values to a workable range.

cmds.listAttr(item, ud=True, st='xgen_Pref')

It's a bit confusing as each time I need to apply a scale to the geometry, which can be confusing to new artists as to what the default scale should be set at.

Would be great if this value was exposed or manipulatable perhaps in a more user friendly way

🙂

Thanks for your help!