Indirect light won't create photonmap.

[hopbin9]

Hi,

I have a project file that fails to render. The indirect light will not generate the output file, and at render time I get a "file not found error".

Start with a new Houdini scene everything works, my other Houdini scenes work fine, but this one scene seems to be corrupt.

Anyone have an idea of how I might resolve this?

Thanks,

[LaidlawFX]

Hi,

I have a project file that fails to render. The indirect light will not generate the output file, and at render time I get a "file not found error".

Start with a new Houdini scene everything works, my other Houdini scenes work fine, but this one scene seems to be corrupt.

Anyone have an idea of how I might resolve this?

Thanks,

Have you tried copying and pasting your node network into a new Houdini file and put a new indirect light there, especially a hip file that the indirect light works in. You can try and bring in the caustic tube example file and see if maybe your render setting are screwing it up. I doubt it is highly unlikely something else is corrupting it, not many things would ever have a reason to link to your photon file.

Outside of that it sounds like the photon file is not being found? did you set up a custom path for it? also if you are writing to a temp directory if everything is animating make sure it is going there. If it is static uncheck Auto-generate Photon Map, and create it perhaps in another file if you need to keep working in the same hip.

[hopbin9]

OMG! Was that EVER hard to figure out. What a pain in the ass to debug.

The problem is a two stage issue.

The error being shown at render time is that the mpam file is missing. So I'm pulling my hair out trying to figure out why Indirect light is failing to create the file, cause the scene file won't render on the farm cause the error message triggers an abort. So I've had to render that scene with out any photon maps (which is taking 1.5 hours per frame right now on 6-core AMDs).

Finally, I figure out how increase the verbose messages shown by Mantra when it's getting ready to render. Turns out the the error message "file not found" is caused by the Prefilter option in the Indirect light, which filters the mpam file after photons are generated. When I turned that option off, the error message went away, but there was still no file!

Increasing the verbose level to 5 finally gave me this message.

"mantra: Aborting photon generation from light /obj/hlight1 due to an extremely low photon storage ratio. Try moving lights closer to your scene."

That should be shown right away. If Houdini had just told me this three days ago, it would have saved me hours or pain and money (coins in the swear jar).

I hope this thread saves someone else some valuable time!