render passes

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Profile Istvan Burbank
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Message 9280 - Posted: 14 Feb 2009, 22:44:49 UTC

For my VFX work I can\'t use BURP to render stuff, because I need the flexibility of render layers. I am not sure how BOINC works, but here is an idea:

As I understand BURP, blender is downloaded, a .blend is downloaded, and a command is downloaded. BOINC runs the command, executing blender and telling it to operate on the file, and specifying which part of the frame to render. I assume that because of some previous advice Janus gave me before that the output frame is stored, then BOINC uploads it to the server. Some to all of this may be wrong, in which case please correct me.

On to the render layers bit; Blender\'s node system has the ability of output nodes. In a simple example, the scene input node might have 2-3 render layers enabled. If the output of each layer was connected to an image output node, each node having a separate root for the file name. The result would be many files per frame. If each frame\'s output were put into a folder, and the folder compressed, then that file could be sent back to BURP. Then a simple script on the server could un-pack the folder, and move each file within the folder to a separate folder, organized by file name root. This would mean that each render pass would be in a folder on the server. Then a video file could be made for each pass, and each pass downloaded individually with CATS.

The un-zipping might be a big task, in which case it could be skipped, or given to mirrors which have chosen to help with this.

A feature that might make sense is to have the combined pass rendered by default, because on the gallery page it might look nicer than just one pass.

I seem to be one to make a long feature list, and my style of coding seems not to be what burp is looking for, so sorry about that. I am asking because I have a huge landscape render, with clouds, and mountains, and tons of lighting, fog and the rest, and I need render layers to make this all work in the final comp, partly because of fog, and because of the lighting. I am right now looking for a way to farm this out, because this is indeed a huge render.
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Message 9282 - Posted: 15 Feb 2009, 9:44:27 UTC - in response to Message 9280.  

The trick is to use multiple render passes - one for each layer. With BURPv.2 you upload the file 3 times (slightly modified to select the active layer) if you have 3 layers.
With BURPv.3 you upload the file once and link it to each of the layers together with a tiny controller file that selects the active layer.

Keep in mind that some layers are more easily rendered locally rather than on a farm.
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Message 9284 - Posted: 15 Feb 2009, 13:13:16 UTC

With that method would each layer be rendered separately? If the layers were split at render, then each frame would have to be rendered once, rather than once per layer. Or did I miss understand what you said?
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Message 9285 - Posted: 15 Feb 2009, 17:08:11 UTC

Since each layer is a seperate session it will be rendered seperately.
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Message boards : Client : render passes