View Full Version : clown pass without background render?

11-23-2011, 12:50 PM
I need a clown pass, but background render pretty much fails every time. I can only render in CPU mode because of a combination of the size of my file and the size of the render. I don't know of too many GPU cards that have 16GB of memory, and that's how much memory it's using to render this.

First, why won't it let me just render a pass without rendering in background? I can almost Never get background render to work. And it also allows the computer to go to sleep. I think it crashes when the monitor goes to sleep...probably because that signal goes to the video card as well? I won't pretend to know why. I just know it crashes, so we've all stopped using it and now no more render-time crashes.

Is the only solution really turn the HDR to zero and assign flat materials manually? That's a bit of a pain. Save, save a copy with alternative materials and setup. Make a change? Repeat. etc.

11-23-2011, 02:25 PM
CPU render results:
clown pass = 45 minutes
manual pass = 9 minutes

I just thought I'd share that. I'm pretty sure that's just because one is background render and one is not.

11-23-2011, 06:39 PM
The clown pass is nasty right now. We are fixing for the next release. The clown pass currently assigns a flat shader of unique color to each part, however, in iray, the flat shader is an emissive shader set to 1 intensity. There is no such thing as a true flat shader in iray. So, when you currently render a clown pass, it is turning every surface into a light emitter which is extremely costly to calculate, especially if any of the parts are high poly.

11-23-2011, 07:11 PM
David, I've just spent a really frustrating couple of hours trying to create a shadow pass and some clown passes using flat materials which of course changes my model into a giant lightbulb. If there's one thing guaranteed to crash Move this is it. Eventually (after multiple crashes) I got my renders using CPU only mode and applying flat materials to the minimum of materials. So can you confirm that the next release will have a proper flat material????

11-23-2011, 07:41 PM
dave is right, however, my concern here is Really background render.

Clown pass Really shouldn't be done in iRay Period. The problem is, if you do something like DOF then you Must use the same sampling or it won't work. And if you have clear parts you'll need multiple clown passes so you can get your work done. Some with perfectly transparent, non-reflective surfaces so you can get your pieces showing through. It's complicated, but can be worth it.

I'm just looking for results on background render though. Mine looks to be 3-5x slower consistently. I want to see if others have similar results.

I'd like a secondary renderer (just an antialiased GPU screengrab is actually fine if it's at full resolution) for quick and dirty selections. They aren't awesome, but it saves your hours of hand selecting bits and pieces.