Integrating 3D models with photography
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# 1 19-08-2012 , 05:37 AM
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Hardware Render: need a depth pass for sprites to be comped in AE

Hi folks. New to this forum. I have a question I've been researching for a few hours now with no luck.

So I have a static field of sprites that a camera is passing through, and I'm trying to figure out how to apply depth of field. Most DOF info on the web has been non-hardware render related, but I don't really have a choice, since I'm using sprites. Hardware rendering only user added image

I've tried rendering in different output formats like .tiff, .rla, .iff. With formats like .tiff and .rla, I would batch render and get the main pass as well as a depth image for each frame, but the only program that can open those depth images is fCheck. It correctly displays the grayscale depth coloration, though the Z view shows my sprites as cards...not as the images they contain. I tried saving that Z image out and using it in AE as a luma matte for the main render, but of course it didn't work in the comp since they're grayscale cards, not images.

I tried the technique listed here by yenvalmar: https://forums.cgsociety.org/archive/.../t-314991.html

...but I never saw a second alpha with Photoshop, even when using software rendering of a polygon object.

I have a very simple understanding of expressions and MEL...not much of a code monkey.

Need help!

(sorry to seem like the guy that joins/starts a thread because I have a question...but I do.)

edit: here's a shot of the sprites I'm working with, and the zDepth result I get from fCheck, both at 25% scale (if it helps)

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Last edited by scentmental; 19-08-2012 at 05:43 AM.
# 2 19-08-2012 , 05:43 PM
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checking in. Still have not found a solution.

# 3 19-08-2012 , 06:40 PM
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Sprite render in mental ray as well have you tried, or render out as PS or tiff that should keep a alpha channel.............dave




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# 4 19-08-2012 , 08:32 PM
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Sprite render in mental ray as well have you tried, or render out as PS or tiff that should keep a alpha channel.............dave

thanks for the reply, Dave.

Mental Ray doesn't seem to produce anything at all. From what I have read, sprites can only be hardware rendered. I tried MR with various image formats, none of them worked.

I tried hardware rendering in all formats, with no success getting a z-depth image that gives me something other than grey cards. Getting the regular alpha is not the problem...getting the "second alpha" that was mentioned in that link is what I was unable to achieve.

# 5 19-08-2012 , 09:09 PM
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I just did this in mental ray must be your settings, I am using maya 2009..............dave

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# 6 19-08-2012 , 11:17 PM
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Thanks Dave. You inspired me to try more mental ray tests. I was able to render those sprites with a new camera, though now I have a slew of fresh problems to deal with. I won't bother to mention them here though.

I'd still prefer to figure out how to get DOF with hardware renders, but this will have to do.

Thread resolved

# 7 06-04-2013 , 06:31 PM
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Thanks Dave. You inspired me to try more mental ray tests. I was able to render those sprites with a new camera, though now I have a slew of fresh problems to deal with. I won't bother to mention them here though.

I'd still prefer to figure out how to get DOF with hardware renders, but this will have to do.

Thread resolved

Hi, scentmental, I am wondering if you can explain a little more about your solution for this. I think I have a similar situation that I'm trying to resolve.

I have a scene that is faking the look of layers of framing foliage using a series of planes (cards, as you put it) with black and white png images mapped outcolor > transparency of blinn shaders. I would like to animate a change in depth of field. A bokeh lens shader on my camera works beautifully in mental ray, but each frame takes a million years to render. I tried creating a luminance depth render but got the "gray cards" effect rather than the shapes of the images mapped onto the planes.

How did you ultimately get a depth image of your sprite shapes? Is there a way to use my shaders in the depth render rather than the surfaceShader? Or maybe map my images to it...hmmm.

Thank you!
C.

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