light cache hangup

[posterus]

hello,
i'm having some issues with a scene where once the light cache calculation begins the estimated time to complete just keeps climbing and climbing. the calculation never begins. the scene itself is about 4.7 million polys, heavy but nothing crazy. i know i've rendered heavier scenes with these same settings on less powerful machines. my system is dual 6 core with 24 gb ram. what puzzles me is i can render a similar scene from the same sources that has more polys, without hang ups.

i searched the forum for this and didn't really find an answer. any ideas? for GI i'm just using default settings for IR+LC. no lights other than environment and default v-ray materials with a little reflection.

thanks,
-joe

[Olli96]

Might sound stupid but i had something similar before, just one or two times, and what helped was to reboot the pc and restart max. After that it was rendering normal.

[Donald2B]

What is your dynamic memory usage set at? You might be swapping to the HDD heavily causing the long LC calc times.

[posterus]

i recall reading a thread about this long ago. i'm not at the office to check but i'm sure it is set at the default of 400mb. what's a good rule of thumb for the dynamic memory limit value in terms of a % of total ram? if i have 24gb what should i use?

thanks,
-joe

[Donald2B]

It really just depends on how much "dynamic" type of geometry you have in your scene. Things like VRay Proxy objects and displacement are usually the big culprits. I only have 8GB of ram in my computer and I usually try to set it around 4096MB. I don't know if there really is a default rule of thumb. I just know that if I have a LOT of the items mentioned above that I know I will have to play with that value to get a balance between static and dynamic memory.

[glorybound]

This is the same issue I'm seeing, and it is costing me a lot of time. Has anybody solved it? 24Gb of RAM here (BTW)

[glorybound]

rebooting didn't help. It climbs to crazy high numbers within seconds, and I can't cancel.

[Deflaminis]

This used to happen back when I was doing commercials on 32 bit way back in the day. There can be a few reasons in my experience.

1) Displacement. Does turning it off in the globals help?
2) Corrupt geometry. Happens a lot, especially when you reload a crashed save file. I usually hide half my scene objects and keep testing until I find the culprit.
3) Do you have another instance of max in memory? Like in the processes? Rebooting would have fixed this however.
4) Does blowing away the render settings and resetting them help? Sometimes a checkbox can get got by accident.

Usually one of those will fix it. If you can't cancel it, it already crashed. In my experience it's a piece of geometry that went bad. Either it has faces right on top of faces (secondary ray bias may help), or it's got unwelded verts or some kind of overlapping problem. Or... maybe a turbosmooth went bad as that does happen.

[kosso_olli]

I had this some months ago. Back then it was the vray carpaint mtl and the vray flake mtl. When I replaced these with other mats, everything was fine.

[glorybound]

I'm talking about this another post. shame on me!

I turned my trees off, rendered some low-resolution tests, turned the trees back on, and now it's rendering fine. It must be a bug.

[tecsun]

Hi Joe,

I written troubleshooting LC back to some time ago, perhaps you can check if you fall into any of that.

http://blog.malaysia3d.com.my/2009/0...ubleshoot.html

[glorybound]

it's a dead link

Hi Joe,

I written troubleshooting LC back to some time ago, perhaps you can check if you fall into any of that.

http://blog.malaysia3d.com.my/2009/0...ubleshoot.html

[Donald2B]

Link works just fine for me.

[glorybound]

Oops! Google Chrome could not find blog.malaysia3d.com.my

Try reloading: blog.*malaysia3d.*com.*my/*2009/*03/*vray-*lightcache-*troubleshoot.*html
Additional suggestions:

• Access a cached copy of blog.*malaysia3d.*com.*my/*2009/*03/*vray-*lightcache-*troubleshoot.*html
• Search on Google:

[vlado]

Hm, works fine for me too... though I don't necessarily agree with what's on the page.

Best regards,
Vlado