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View Full Version : Can Combustion read the g-buffer data from a single image?


trask
02-08-2008, 03:19 PM
I need some help on finding a good way to color correct individual objects of a render in post-production.

My first attempt was to use the G-buffer info from the render in Combustion (4). I assigned an object a unique g-buffer channel, rendered, and saved out as an .rpf. Combustion, however, would not read the g-buffer info. The only way Combustion would see the g-buffer data is if I rendered out an animation sequence of .rpfs. Is there anyway to read g-buffer info from single images in Combustion?

The second solution I tried was to assign the g-buffers to the objects, and render out the 'render elements' object id and bring it into Photosohp. This method works, but its a pain to save out all the selections; not very efficient.

I'm aware of Cebas' .psd g-buffer exporter plugin, but I'd rather not spend more money if the same thing can be done with Combustion. So... the million dollar question: Can Combustion read the g-buffer data from a single image?

PiXeL_MoNKeY
02-08-2008, 06:01 PM
Did you examine the g-buffer using the show g-buffer operator? My guess is that the information you are expecting is not there. Combustion will read whatever is stored in the file.

-Eric

trask
02-08-2008, 08:09 PM
Yes, I used the Show G-Buffer and got, "Show G-Buffer: The Z Buffer Channel is not available". The funny thing is that it works fine if the footage is an image sequence.

So it is possible for Combustion to read the G-Buffer of a single image?

I attached a part of the screenshot. Do I have my workspace setup correctly?

Thanks!

trask
02-08-2008, 08:49 PM
Something worth mentioning: I'm using Mental Ray as the renderer, does Mental Ray output G-buffers?

PiXeL_MoNKeY
02-09-2008, 01:12 AM
Again, as long as the information is there combustion will read it. According to that error there is no zbuffer in the image it is trying to access.

-Eric

trask
02-11-2008, 02:50 PM
Found the solution!

The reason the image was not storing the buffers is because I was using the 'save as' command from the render window. Saving this way will only grab 4 channels (rgba). The image has to be saved with an output path *before* it is rendered in order to hold all of the extra rpf/rla info. ...Probably a 'well duh' for most, but oh well -it works!

Thanks to eodeo from the Area forums!

Thanks pixel_monkey for the help!

PiXeL_MoNKeY
02-11-2008, 06:17 PM
Actually Save As will work, but you have to enable the channels before rendering. This can be done by script or by opening the render dialog setting the settings and uncheck Save Image. The VFB/RFW/(whatever they are calling it now) will only render, store, and save the channels it is told to. If you don't enable them before render it will only produce RGBA channels, you can see this easily clicking on the channel drop-down. If a channel you want isn't in the list it can't be saved.

-Eric

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02-11-2008, 06:17 PM
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