Vray Irradiance Mapping

[Jinmu Staddon]

It is possible and often very useful to be able to use the stored Irradiance Map from a previous rendering with the "Incremental add to current map" mode. Is there a way then to do an "incremental add to file"? Sometimes I'll have a large rendering that takes a very long time that I want to come back to after a few days and do a new camera angle. Obviously, the previous irradiance map is no longer in memory, so I can't just add to it. Being able to add to a file would save lots of time, which is especially useful since I'm constantly on tight deadlines. Any thoughts?

[BrianKitts]

you might be able to start a rendering with it set to irradiance from file that way it loads the map your existing map, cancel the render then switch to add to current map.

 

There are tools out there that will allow you to create a new irradiance map and merge it with an existing map. But in that case you still have to full calc a new map, so theres no time savings, and it's really not worth the effort.

 

How long are your irradiance calcs running? Typical irr calc's only run 10-20 mins depending on your machine....even in my worst scenes at 4k full production settings at most irradiance maps take around an hour.....If you're running longer than that I would suggest optimizing your render settings.

 

The only time I bother saving irradiance maps is when I'm doing animation, otherwise it's not worth the extra steps and the possbility of legacy information failing to render new changes properly.

[Jinmu Staddon]

It tried starting the rendering with the saved map, but it doesn't load it into memory. It will actually leave the most recent map (that wasn't from a saved file) in memory. I know that you can use Irradiance Map Viewer to merge files, but that not necessarily all that useful. I suppose it could be if you to two very difference camera angles, then merge, which would allow you to quickly do angles in between if you needed to. I guess this is basically what one does for an animation, adding to an irradiance map every 10 frames or so.

 

I'm running an iMac with Windows 7 x64 with an i7 870 (2.93 GHz), 8GB RAM

 

The calc phases are taking about 1.5 hrs (lots of reflections/refractions and high poly count due to import from other software and high res--5000x3000--for large format print). Normally this wouldn't be so bad, but deadlines tend to be so tight I'm trying to save time wherever I can. Also just trying to satisfy my own curiosity since it seems like a pretty natural way to build irradiance maps.

 

I should also spend the time to optimize my IR settings though. That would probably save a lot of time in itself.

[Jinmu Staddon]

Actually, I just tried it again, and it works! I just rendered "from file" and canceled it, then did "incremental add to current map". I saved over the original then did "from file" again and saw that data from both the new camera angle and old camera angle were in the file. I don't know what I did wrong last time, but it does indeed work.

 

Thanks a bunch!