XGEN Groom to Primitives Error

[Anonymous]

I am working on adding fur to a deer. The deer has very short hair in the head area, and longer hair on the body.

I am able to shrink the hair on the face using the Lengthen groom brush using negative values as indicated by the yellow groom cards.

The issue:

Even though the face is showing no groomable splines/cards after I shrink them down with the lengthen brush, that information does not translate over to the primitives tab. There is still hair on the face when there shouldn't be (according to my groom). Is there a setting that causes this?

I also have tried to add a painted ptex map to control length, but do not like the results.

Possible Solution?

Should I just make several different card geos to grow xgen from for specific parts of the deer or is there a better option within xgen to generate hair where I exactly want it?

[Michael_Todd · Accepted solution]

Paint a density mask to ensure no primitives are generated in the areas you don't want them to appear.

You could even try using the expression from the length parameter in the density and width.

[Anonymous]

I did try that.

I painted a mask to make sure no fibers would grow on face.

I plugged into the length parameter (it indeed did mask the face), but my body hair that I had groomed changed significantly. It was using white at full length I guess. So i had to paint down and I never could get it back to my original groom.

I guess I should have started with the mask, and then started to groom?

[Michael_Todd]

Did you paint the maps using the 3D paint tool? If so, there's an issue with the falloff for the brush, where only the very center of the brush is true black and as a result, you can still get hairs where it looks like there shouldn't be any.

Try painting with a hard brush then smoothing the edges. Then you should get true black where you need it.

Cheers

[Anonymous]

I do not think so. I clicked the paint icon, and it automatically turned the model white for me. I was easily able to paint the mask. I then saved.

The black area worked perfect. No hairs.

The problem was the white area, which did not respect the grooming tools properly. It DID respect the length parameter. I was hoping the groom would override that but respect the mask.

[Michael_Todd · Accepted solution]

The length map generated by groomable splines is just a multiplier on the length value set in the grooming tab. White is just 1 so the length there will just be whatever value is set for the length.

You can stack painted maps in the expression editor, using a secondary map on top of the map created by using the grooming brushes.

$a=map('${DESC}/groom/length/');

$b=map('${DESC}/paintmaps/length_mod');#3dpaint,30.0

$a*$b

The  * acts as a multiply function, you can also use + - /, % and ^, add, subtract, divide fmod or Power, as outlined in the editor help tab and XGen documentation

XGen Expression Editor Docs

[Anonymous]

Where do I select the hard brush, and how do i smooth?

Im new to paint system in maya.

Thanks for all your help so far!

[Michael_Todd]

with the paint brush active, just double click on the active tool icon in the toolbox on the left:

this will open the tool settings window for the 3dPainttool

Select the brush indicated to paint the mask then witch from paint mode to blur or smudge mode to smooth the transition.

[Anonymous]

My brush system is not working like that. 

I have followed the instructions and as i try to smooth the transition with the smooth brush, this is what i get. Sharp, jagged, faceted transitions.

Please see the attached.

[Michael_Todd]

That's because your meshes UV's are not contiguous. They appear to be split up into lots of shells. The blur and smudge tools don't handle shell borders very well (turning on extend seam colors can help) 

It would be better to create a more unified UV layout as the paint tool is quite old and not very good at handling UV shells, In fact it can't handle UV tiles at all, and can only work in U1 V1.