rendering issues with hair system

[thefreshestever]

ok, i got a big big problem here, deadline is in 2 days...

i have this shot i need to render in high quality, at least 2000x1500 px.... the soccerfields grass is a hair system, color driven by a decal.

when i rendered it in vga-resolution for a test with low hair-density (5%) everything looked fine, but when i increase the density parts of the hairsystem renders white, not green anymore... the higher the density-value, the more parts of the grass are rendered white. i use a skylight rig with 25 lights, wich was no problem in the past, also in combination with a field of grass made with hair with similar density-values and size...

i tried almost everything: rendered it on 2 different computers, pc and mac, tried it with and without skin shader, different resolutions, still got the same problem...

 

does anyone have experience with this kind of rendering-issues???

 

screenshots/testrenderings attached...

[3DArtZ]

My solution would be to do this without the hair system.

other then that.... what format is the decal, how big is it file size?

[ruscular]

My solution would be to do this without the hair system.

other then that.... what format is the decal, how big is it file size?

The file size may be too much to handle. I would try rendering the field as a separate pass, the closer you are to the chair and subject increase grass count. Then maybe composite the subject and chair on top with high grass count around them only.

 

does the grass need to be animated? If not consider using a one render pass for the grass as your background plate, and render animated grass just around the subject activity space.

 

if you have a shot at one angle. you could do a single render, and then paste decal onto grass object at the angle of your plan shot, and then use the area immediate to the subject in chair with animated grass.

[thefreshestever]

My solution would be to do this without the hair system.

other then that.... what format is the decal, how big is it file size?

 

thanks... i can´t do it without the hair system, some renderings i´ve made before for this client were with hair-grass too, so they would ask why this new one doesn´t look as cool as the others...

 

the decal that drives the hair-color is a 1mb jpg, 2400x3560px... i´ll reduce the resolution and save as tga and try to render it again...

let´s see what happens...

[thefreshestever]

ok, same thing with half of the decal-resolution and tga-format... next thing i´ll try is another lighting setup...

[thefreshestever]

same with normal 3-point lighting... but i just had a thought, i´ll try that...

[thefreshestever]

dammit.... i thought it was because of the one big patch my soccerfield was made of (once i read in a turorial that one should avoid that large patches), so i made a mesh with 10x10 patches and then decaled it again... when i rendered it this happened... i´m just loosing my mind here, please help!!!!!!!

[mtpeak2]

I would need to see a project file and images. Don't need props or character, just the ground plane, hair material and decals.

[3DArtZ]

what version are you working in?

v14, 15?

If not v15 then you could post the project file, minus the guy and other props and let us have a go with it.

 

I wonder if the patch normals are pointing in the same direction? would that make a difference?

[thefreshestever]

i´m just rendering a new test, maybe it works now... i guess it will take about 20 minutes, when the problem still appears i´ll post the project... thanks ahead mark...

[thefreshestever]

what version are you working in?

v14, 15?

If not v15 then you could post the project file, minus the guy and other props and let us have a go with it.

 

I wonder if the patch normals are pointing in the same direction? would that make a difference?

i´m using v15.... the normals are all in the same direction, otherwise the hair would grow downside on those patches...

just rendering another try... thanks for your help...

[thefreshestever]

ok... GOT IT!!!! if you could see my big smile now!!! there just were too much decals... i had one decal to color the ground-mesh and one to color the grass, just merged them together and used only one decal in two instances, one for diffusecolor of the mesh and one for diffuse of the hair system... my test-render with 15% hair-density rendered fine... let´s see what i get with 40% density, higher resolution and multipass... but i´m pretty confident right now... thanks guys!!!