Fur Painting

[up4]

Hi,

 

So while following Andrew Burke's fur tutorial, my computer (Win 8.1, 2x SLI GTX 780, 2x 8-code Xeon, etc.) chokes hard on the fur density paint node. It's really slooooooow. And my geometry seems sparser than the one in the tutorial so it's weird. Are there some tricks to work this out? NVIDIA driver settings perhaps? I know that some antialiasing options make Houdini angry and I cannot use GL 3.3 viewports because there thin curves (gnomons, transformation controls) are not displayed. I'm using GL 2.1.

 

Also, the diffuse maps already contain some baked hair and I can easily extract to have density data. However the maps are UDIM and it was a pain to set UDIM in the shaders and the viewport so I would like to avoid them for painting fur. But if it comes to that, has anyone used UDMI fur density maps? If so, how was the fur sops modified to make it happen?

 

Regards,

 

Vincent

Edited October 29, 2014 by up4

[mawi]

Hi,

 

So while following Andrew Burke's fur tutorial, my computer (Win 8.1, 2x SLI GTX 780, 2x 8-code Xeon, etc.) chokes hard on the fur density paint node. It's really slooooooow. And my geometry seems sparser than the one in the tutorial so it's weird. Are there some tricks to work this out? NVIDIA driver settings perhaps? I know that some antialiasing options make Houdini angry and I cannot use GL 3.3 viewports because there thin curves (gnomons, transformation controls) are not displayed. I'm using GL 2.1.

 

Also, the diffuse maps already contain some baked hair and I can easily extract to have density data. However the maps are UDIM and it was a pain to set UDIM in the shaders and the viewport so I would like to avoid them for painting fur. But if it comes to that, has anyone used UDMI fur density maps? If so, how was the fur sops modified to make it happen?

 

Regards,

 

Vincent

Hard to say whats wrong. However there are a few things I usually do.

  -Dont display the fur while painting. The whole fur network recooks and it can get a bit slow.

  -By default the skin network is time dependent if you got animation coming in. I use to work on a time freezed mesh and then copy or transfer the attributes back. This also makes it much easier to handle when the model department comes up with the great idea to add a few loops here and there.

 

Havent done fur maps with UDIMs but the fur density map goes into the skin-cvex shader found in yourFurNode/fur/shopnet/skinshader and it shouldnt be that hard to modify to use UDIM.

 

 

Edit. Or its a GL problem wich I really cant comment on. Is it always slow when using the paint SOP?

Edited October 30, 2014 by mawi

[illuMinator]

Concerning the UDIM:

 

For our project "Helga" (http://forums.odforce.net/topic/20241-animated-short-helga/) we have a UDIM texture workflow as well. I made an HDA that we use to load in our UDIM textures. The nice thing about it is, that you do not need to modify anything in sops. You can use that for density maps, but you need to make a small change.

 

Like mawi suggested, go to yourFurNode/fur/shopnet/skinshader and use the HDA instead of the map parameter. In the fur context it will give you an error, so you need to unlock it, go inside and use a "Fur Skin Global Variables" node instead of the uvcoords node. 

Then, on the HDA interface just specify the path to your density map and type <UDIM> instead of the UDIM number. For example: .../density.<UDIM>.rat

 

The HDA uses an Inline Code node to replace the <UDIM> tag with the number that it calculates from the skin uvs.

 

udim_texture_path.otl

 

 

[up4]

@mawi: thanks hiding the fur indeed speeds the painting up a bit, but it is still slow and somewhat inaccurate since it's vertex-based so I'll try baked maps.

@illuMinator: thanks! you did Vex inline string manipulation you deserve an odforce master status! do you happen to have something working for color maps in the viewport too? ;-)

 

thanks to both of you

[illuMinator]

It took me forever to make that little string replacement happen in vex. It is certainly not the best language for that

 

Unfortunately I don't have a solution for UDIM textures in the viewport. Would be really cool to see that working.

 

Have you considered painting your density maps in Mudbox? I think it is much more convenient than painting attributes in Houdini. And it has the advantage of not being screwed when the mesh topology changes (as long as the uvs stay the same, of course).

Of course, it has the downside that you do not get immediate feedback, but I think it is still more efficient to do it that way.

[up4]

I'm setting up MARI to paint all my fur related maps (density, white density, length, cut, thickness, frizz, clumping). And then use blender to comb guide hairs. I'm not sure I'll need combing after all of this. I'm practicing on DAZ geometry and original textures. 

[illuMinator]

Mari is probably even better. I just use Mudbox because it is really easy to learn

[up4]

Been a while, but I finally had time to go back to this and it worked. I posted something here.

 

Is it possible to do the same with frizz, clumping, thickness and length. If so, do you know where this would be?

 

Thanks!

 

Vincent

[up4]

Oi! Just found the other parameters I asked for in the "guideshader". Will try to apply UDIM there.

[pelos]

I don't recommend using udims for driving the fur in any application, even a map low as 1000*1000 is enough to tell the engine where and what the fur should do.  don't forget  you wont be seeing that texture in the frame, you only using it to drive parameters.

 

we usually have 2 uv sets,   one for the textures, udims and all that stuff, (usually one map for the head, and one for the body, depends the character might be broken into limbs) and another simple uv for driving the fur.

[up4]

Hi Pelos, first it is grand of you to commit such a vast amount of work for free. I'm currently looking at the Fabio videos right now. I'll post more on that on the other thread.

 

UDIM is not an option to me because that's how the skin UV is unwrapped and I do not want a second UV set because I want to be able to place fur (I actually use Illustrator) on top of the actual skin textures (sometimes skin textures already contain baked-in hair that first need to be removed). But I pretty much found all the necessary hooks for it now, so I'm good. Thanks!