help noob with runaway building light cache...

[gfriedman]

Hi

For some reason when I go to render my scene the time estimate for building the light cache just perpetually climbs reaching many many hours - i have a feeling it's actually hanging and not processing. I dont think my scene is particularly complicated. Any ideas why this might be happening, and how I might stop it?

 

thanks!

[Crazy Homeless Guy]

Check your materials. You probably have an architectural material or something in the scene. Switch it to a Vray material.

[gfriedman]

thanks for that. I'll check that out. Are there any tools in max for analyzing that sort of stuff - that could help locate the particular object or material causing the problem?

[Crazy Homeless Guy]

When trouble shooting I usual use the layer manager, and turn on a handful of layers at a time, and then render. If those layers render fine without crashing or whatever, then I turn them off, and turn on the next handful of layers, and render them. Usually you will run into a set that causes the file to crash.

 

If I am looking for incompatible materials, I simply use the material browser to locate the ones that are not compatible.

[gfriedman]

ok. i think I found the culprit - but the problem may be slightly different than what you were suggesting. I am having trouble with a couple of elements I recently merged into my model - boths were large stretches of sidewalk and roade and in order to texture them i made massive jpegs in the aerial view. This seemed to be the only way to deal with irregularities in the road and the roundings at corners. So what is it with these textures that could be problematic and how can I fix it? They are both vray materials btw...

[erickdt]

Also, displacement and/or VRay fur will make light cache calculations sky rocket.

 

E

[gfriedman]

im totally baffled - it's neither of those things...I'm going to see if i can package the file up with textures to be attached here

[Crazy Homeless Guy]

If you put a material over ride on the file, does it still skyrocket?

[gfriedman]

no, that solves things. could it be these massive jpegs? they are like 60 mb and 15000px x 15000px...i know that sounds ridiculous - i wasnt sure of a better way to texture my road...

[Eric Sosa]

reasons

• huge bitmaps
  
• materials with high subdivisions (over 30)
  
• ligth cache settings; high subdivisions (over 2000)
  
• ligth cache settings; sample size under 0.005
  
• irradiance map with HSph sub over 50
  
• irradiance map with Inter samples over 50
  

I could imagine that no.2 (the vraymats subdivisions) is the your particular problem Gabriel.

 

hope it helps.

[gfriedman]

from playing around I think it must've been number 1 actually. I never touch my subdivisions in my materials...but when i trimmed out the material it seems to have worked. I didnt know that this could be an issue.

 

thanks so much

[FlytE]

I think its something to do with autoback happening during a lightcache calculation... I could be wrong because it doesnt happen every time but Im 90% certain thats what causes a hanging light cache. Next time it happens, look at your autobak files and check the time on the latest one, fiver says that it was saved at the same time as your light cache was being calculated.... another fiver says if you try and open it its also corrupt.

 

I have had this problem for years with vray and it seems to surface every now and again. Its a right pain in the arse because it appears the only option is a forced shutdown of max which by default always seems to corrupt the file i am working on AND the backup.