error message caused by lightmap

[sv]

Hello All,

This might strike some people as stupid - if it does please let me know where we have gone wrong. Sent the animation to our renderfarm, using lightmap as secondary bounces. set to flythrough. On all nodes apart from the one that finished the frame first, the following error message appears:

Cannot create a file that already exists

For primary bounces, we have already calculated and saved an irradiance map, and are rendering from this through backburner.

Any thoughts?

[egz]

You get the error because every node is trying to create the same lightmap file. You need to calculate the lightmap like you calculated the irradiance map: on one system in flythrough mode, then load it from file in the final netrender.

[sv]

Good,

this is what was the case - for the last half hour or so i have created a lightmap - rendered on one machine, for an animation of 350 frames, with the following settings:

subdivs: 1800
Sample size: 0.01
Pre-filter on 60
Filter: Fixed
Filter size 0.04

My only concern is: the size of the .vrlmp file is 525meg! As i will be sending this over a renderfarm, i am aware that backburner has problems sending large files accross the network, especially when multiple machines are going to be accessing them at the same time. Does this look right to you?

[RErender]

I have not tried it but does it work to render every nth frame in the flythrough?

[sv]

good point....
i'll try it, i'm not sure either. But is it right for the lmap to be so large? Isn't this going to cause problems with backburner?

[RErender]

Yes, it would probably be a problem with backburner, you would likely have to copy it localy to all the slaves. That is why I suggested trying every nth frame, If you did every tenth frame "maybe" the file size will be 1/10th as well. I am looking forward to hear if it works.

[sv]

Cheers man, I'll get on it tonight and let you know how it works out. It does pose a problem though if file sizes are still massive. Lightmapping is by far the quickest way for producing secondary bounces, and if i can't use it over the network i'll be annoyed. When you say copy it locally, do you mean saying:

render from file: C:/GI/cam1.vlmap

And creating this diretory on each machine?

[sv]

In the time it took me to eat one large apple, i rerendered the lighmap with slightly lower settings - subs at 1000, sample size at 0.02, and at every nth frame of 10 - but i don't think this option worked. I set the lightmap to flythrough, then clicked nth frames 10, but as you only need to render out one image for the lightmap to calculate the entire animation, this optinon became greyed out. I am not doing fixed pre filtering for the reconstruction phase, and also I also am rendering out at half of the final image size, just as i have done for the IR map. (i am not entirely sure this can be done, but i am presuming so)

The file size was 499meg.

Still pretty big, so i will try and copy it locally in the way i described above. Will see what it looks like tomorrow - got to be better than this morning where some frames were ok, and the others were more or less full shadow black - obviously the saved GI maps hadn't been passed to the renderer for some reason, resulting in no lighting. Horrifying to see, but quick render times non the less!

Or would it be better just to have the lightmap settings on single frame - this way it would be calulated every frame on each machine, and i wouldn't have the problems of each node trying to save the lightmap file and returning an error because the file already exists?