View Full Version : Beware of Image Based Lighting....

01 January 2005, 02:33 AM
After many weeks of random crashes, I've found that the IBL node is the source of the problem, and it is very unstable on Linux. I've been using it only as an enviroment map for doing ambient occulsion, which is the simplist the node can be used for, but after lots of testing I've found it causes crashes even if its only being used for a backgound image.

The best part about the crashes is that in some files if you just hit the "render" button over and over again it will crash after the 4th or 5th time, even though NOTHING changed in-between renders. I haven't figured out the exact combination that creates the problem yet, but I'm getting closer. This bug happens even in really simple files.

Thanks Alias. :thumbsup:

01 January 2005, 03:58 AM
Is this occuring from within the gui or does it happen when you render from the command line as well?

01 January 2005, 11:59 AM
What signal does Maya give when it crashes? The ever-wonderful signal 11? Have you tried keeping a top running while you're working to see if it's a memory leak?

There is a possible workaround: if you're just combining an environment map with an ambient occlusion pass, it's only a couple of hours work to write a shader that'll read an environment map (possibly using bent normals), as long as you don't care about proper raytraced IBL; even then it's pretty trivial: I could knock one up in a few hours.

01 January 2005, 11:52 PM
Not to get too far off subject. But playmesumch00ns, I would be interested in at least discussing some possible shading networks that incorporate the dirtmap shader and bent normals. I am especially interested in figuring out the environment map lookup.

01 January 2005, 02:07 AM
maya encountered a fatal error

Signal: 11 (Unknown Signal)

Ahh yes, my favorite error of all. The crashes are happening interactiveally, and it doesn't seem to be a memory leak. And if you can whip up a slick new shader to get around this, then by all means please do. :thumbsup:

01 January 2005, 04:54 PM
I just like the way how Maya magically evaporates, particulary rewarding when dealing with large scenes and not saving every minute or so.

01 January 2005, 08:37 PM
It's only happening on Linux, is it? I use IBL to test render quite frequently and I have yet to have a problem. I was gearing up to use it for final lighting setups as well but perhaps I will have to reconsider... I'm on WinXP though, and you said Linux, so is it isolated at the moment?

02 February 2005, 03:57 PM
I found a work around last night. If the IBL node has its "primary visibility" turned it, then the random crashes start happening. I did about 50 renders with it turned "off" perfectly, but then on the first render when I turned it "on" it crashed hard. The good news about this is that I never wanted to see the IBL in the background of my render anyways.

02 February 2005, 04:10 PM
Just to throw in my two cents: I'm on WinXP Pro (no servicepacks, just some little hotfixes, hw: A7N8X-E w/ AMD2600+) and I never ever had any kind of problem with the IBL.

02 February 2005, 09:22 PM
im using Linux here, and its not Red Hat, and i never had that problem, most of the images i rendered were using IBL, with the primary visibility on. :shrug:

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