Long Render Times With Fur And Mental Ray

[kloveridge]

I have a relatively simple object that is smooth bound to a 10 bone skeleton. The object has fur on it. (Imagine a flag with fur fluttering in the wind.)

Anyway, I am using Maya 8.5 with mental ray (software renderer will do this as well.) Anyway, I send off the frame to the renderer and there is a 8 minute wait with the message "Calculating...Hit escape to abort." What exactly is calculating here? Is there a way to cache off the data it is calculating as can be done with Hair?

Once this calculating is done, the actual rendering will take about 30 seconds to render.

Any suggestions on how to improve this would be helpful.

[boradayioglu]

QUOTE(kloveridge @ 06/06/07, 01:21 AM) [snapback]267551[/snapback]
I have a relatively simple object that is smooth bound to a 10 bone skeleton. The object has fur on it. (Imagine a flag with fur fluttering in the wind.)

Anyway, I am using Maya 8.5 with mental ray (software renderer will do this as well.) Anyway, I send off the frame to the renderer and there is a 8 minute wait with the message "Calculating...Hit escape to abort." What exactly is calculating here? Is there a way to cache off the data it is calculating as can be done with Hair?

Once this calculating is done, the actual rendering will take about 30 seconds to render.

Any suggestions on how to improve this would be helpful.

Its probably calculating the area values and creating equalizer maps, which are on in fur render globals by default. You can either turn them off, or pre-render them.

bora dayioglu
http://www.borafx.com

[jp-mardonez]

Maybe this tips are too late but everyone can benefit from them.

• If the precalculation of fur is several minutes and the render is 30 seconds, I guess you have over 500.000 fur hairs, try to reduce them. Try increasing the base width to fill the surface instead.
• Maybe the segments of fur are way to much, try the lowest number without killing the desired look.
• Use MR volume method with scanline, no ray tracing, and detail shadows.
• Avoid fur tip widths inferior than 0.01, because the fur will flicker, use tip opacity to compensate.

[kloveridge]

Thank you for your help. It looks like the big culprit was the segments. I had some other examples where the fur would take forever and eventually crash my machine. I think my scenes were overrunning my machines memory.

[kafl]

Hi there

Thank you for all this helpfull info. I was playing/testing fur rendering with very simple fur, on objects with 30.000 faces, and it took forever to render out. Now i tried to turn of the eqyualizer map rendering, and now it takes 7 sec.... amazing.
I will look into the helpfile to understand exactly what i just turned off, but now I have another question.

Just for testing I make polygon sphere, crank up the the subdivisions to 200 so the faces is 40.000. I animate it very simple in any transform axis and it runs smoothly, then I apply new fur description with default values and even though i only see about 100 (guessing here) fur hairs, it runs super slow.

Any ideas on how to make it run faster? is it possible when using this high poly numbers as base? or is the only solution to just use lowpoly models for the fur attacment?

Thank you very much
Karsten