PDA

View Full Version : Reducing Fiber Fx rendering times?



sammael
02-25-2009, 07:35 PM
Hey all, I'm just starting to look into Fiber Fx for the first time and I seem to have a bit of a problem.
I am making a character using FFX for the small amount of hair on his body with weight maps to control the scale and density. On decent render settings the character with sss, GI and aa takes about 12-15 mins per 800x600 frame. The same character with the FFX turned on (not straying too much from the default hair settings) takes between 1-2 hours to render depending on aa settings etc.
If I turn off the geometry and just render the hair with radiosity, aa etc the render will take around 7-10 minutes. If I switch off the simple skin material on his body the render time is greatly reduced as well.
I cant understand why its taking so long, is there a way to optimize or reduce render times without compromising the quality too much? Is this something to do with using a combination of simple skin and FFX?
Any insight would be appreciated,

Cheers!

Tranimatronic
02-27-2009, 11:51 AM
I had the same problems a couple of weeks ago with a character I was doing.
In the end I added an extra layer of polys under the characters skin for the hair rather than a weight map over the eniter mesh. This cut render times significantly, I also dumped the sss and relied more on the texture map. IMHO good lighting & the bloom effect will more than make up for the lack of SSS. Also the subdivision amount made a difference - I reduced it to 16 from 20 and still got most of the detail.
I never got round to rigging this guy so I dont know how the hair polys would react if the weights were slightly different to the head mesh, but I do plan to finish this sometime, so Ill keep you updated if youre interested.
In the end I got render times of ~10 minutes per frame on a steam powered single core pentium4 @ 1024*768 which I thought was pretty respectable.

ps. make sure to use 9.6 because 9.5 crashed every 30 seconds.....

http://assets.cgsociety.org/challenge/entries/23/17064/17064_1230098220_large.jpg

Tranimatronic
02-27-2009, 12:16 PM
Im wondering whether the weight map is calculated using the original mesh (the one the weight map is painted on) or the subdivided mesh (at rendertime). That would probibaly explain the huge leap in render times between a mesh of 1000 polys and 2,000,000 ? anyone know the answer to this ?
T