clipka wrote:
> Mike Raiford schrieb:
>> The following is a minimal scene to reproduce this. It requires a 
>> perfect storm of using a micronormal, blurring, and a high amount of 
>> dispersion samples to cause POV-Ray to run away with allocating memory.
> 
> The memory consumption is alarming even without the dispersion, rising 
> as high as 1.6 GB for a 800x600 render on 8 threads.

Oh, wow. I thought it was the dispersion + micronormal.

> The reason appears to be a humongous amount of crackle cache data: The 
> crackle pattern is only semi-procedural, requiring random values to be 
> computed and cached for subsequent queries, with a fixed amount of data 
> per unit-cube in crackle pattern coordinate space. Using crackle for 
> micronormals is therefore a bad idea: Scaled smaller than the density of 
> actual ray-object-intersections computed, it will eventually lead to a 
> separate crackle cache entry being created for each and every 
> intersection. Memory consumption will then grow with every additional 
> ray being traced, which is fatal with e.g. focal blur or dispersion that 
> create a huge amount of rays per pixel.

Makes sense...

> With bumps instead of crackle, memory requirements stay virtually at 
> idle level. Given that you can't make out the crackle structure at such 
> a scale anyway, that's the way to go. If you need a different 
> distribution of "slope probabilities" than the standard bumps pattern 
> (e.g. to simulate a basically polished surface with comparatively sparse 
> microsopic scratches), you may want to try bumps with a slope_map.

Thanks for that. Honestly, I don't know why I was using crackle in this 
scene in the first place.

(I've been going through old test scenes, doodles and such with 3.7 to 
see how they render, etc...)



-- 
~Mike

Post a reply to this message