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Grashock
07-16-2009, 04:56 PM
I've got a glass sphere with some extrusions, as a test for some stained glass windows. I'm using this as a test scene to try and get the light passing through the windows to cascade down on the rest of the objects in the scene. But I'd also like to get those same colored photons(?) to pass through some fog.

This is a screen shot of my current setup, it all seems to be pretty standard fair for glass/colored liquids only that I have a image plugged into the color channel rather then a ramp/flat color. The other image is an example taken from mentalimages.com


http://home.comcast.net/%7Elucas_moore/pwpimages/WindowTest1.jpg

http://www.mentalimages.com/uploads/pics/dustyroom_001.jpg

MAV4d
07-16-2009, 06:12 PM
Check your normals. and Include the object in the fog bounding box.


you want to use the mr parti fog, to work with photons.

InfernalDarkness
07-16-2009, 07:57 PM
...you're using dielectric material, instead of mia_material_x?

But yes, you'll need to use the parti_volume material in a bounding box surrounding your scene. It's a bit tricky sometimes, but keep at it and keep asking questions if you get stuck!

MAV4d
07-16-2009, 08:16 PM
dielectric material is much faster than the mia materials. At least from my experiences

Grashock
07-16-2009, 09:23 PM
I've gotten a bit father into it. This is the result that I have now:

http://home.comcast.net/%7Elucas_moore/pwpimages/StainedGlass3.jpg



Still not quite what I'm looking for. I did try and look for 'mr parti fog' but was unable to locate it. I did find 'parti_volume' but I'm kinda at a loss of where to place it into the tree. It's located in the 'Volumetric Materials' second of mental ray in the Hypershade, would I plug it into the material shader slot or the volume shader slot. I know this is probably a pretty elementary question, but I'm still pretty new to using mental ray materials, and I'm pretty much learning by brute force. Any helpful crumbs you could throw my would would be most appreciated.

Thanks for what you've done so far. I know what I want to achieve is possible, just a matter of working through it.

InfernalDarkness
07-17-2009, 12:38 AM
Looking good so far...

One way to get the color to transmit would be to use photon shaders as well. Volumetrics in mental ray are a real pain in the ass, so if you're having trouble, it's not just you. In most apps, you simply turn on volumetric lighting for a particular light and you're done. In mental ray for Maya, you've gotta go all over the place to get anywhere... Obnoxious, but the end results can be amazing.

Kev3D
07-17-2009, 03:11 AM
Why are you using a sphere for this test? I only ask because it introduces a whole lot more complications then a flat window due to the way light refracts through a sphere. I did a quick google search for marbles and they all had a bright caustics spots under them. I don't think you'd get either straight rays of light or any discernable image in real life.

Grashock
07-17-2009, 10:05 AM
Why are you using a sphere for this test? I only ask because it introduces a whole lot more complications then a flat window due to the way light refracts through a sphere. I did a quick google search for marbles and they all had a bright caustics spots under them. I don't think you'd get either straight rays of light or any discernable image in real life.

I was thinking the same thing. My original test scene was of the window, but I had a lot of issues as I was brute forcing my way through the shaders. I'd get crashes and such. I'll be playing around with it as a window now that I have a better idea of how the shaders work.

Looking good so far...

One way to get the color to transmit would be to use photon shaders as well. Volumetrics in mental ray are a real pain in the ass, so if you're having trouble, it's not just you. In most apps, you simply turn on volumetric lighting for a particular light and you're done. In mental ray for Maya, you've gotta go all over the place to get anywhere... Obnoxious, but the end results can be amazing.

Thanks, and that's exactly the point, MR can be a real pain in the arse to work with but it almost always comes out with a high quality render.

I'll keep plugging away at it, and post any progress. Thanks for all your help guys!!

Grashock
07-17-2009, 10:10 AM
Why are you using a sphere for this test? I only ask because it introduces a whole lot more complications then a flat window due to the way light refracts through a sphere. I did a quick google search for marbles and they all had a bright caustics spots under them. I don't think you'd get either straight rays of light or any discernable image in real life.

I was thinking the same thing. My original test scene was of the window, but I had a lot of issues as I was brute forcing my way through the shaders. I'd get crashes and such. I'll be playing around with it as a window now that I have a better idea of how the shaders work.

Looking good so far...

One way to get the color to transmit would be to use photon shaders as well. Volumetrics in mental ray are a real pain in the ass, so if you're having trouble, it's not just you. In most apps, you simply turn on volumetric lighting for a particular light and you're done. In mental ray for Maya, you've gotta go all over the place to get anywhere... Obnoxious, but the end results can be amazing.

Thanks, and that's exactly the point, MR can be a real pain in the arse to work with but it almost always comes out with a high quality render.

I'll keep plugging away at it, and post any progress. Thanks for all your help guys!!

Grashock
07-19-2009, 05:03 AM
So I was looking at it, and discovered alot of the docs that I have read about doing the effect I'm trying for has been accomplished frequently in previous versions of Maya, but 2009 appears to have a issue with it.

Below is an image of the exact same scene. Neither is very high quality, but proves the point that something was changed, and for the life of me I haven't been able to locate it. Any ideas?

http://home.comcast.net/%7Elucas_moore/pwpimages/2.jpg

InfernalDarkness
07-20-2009, 07:53 PM
...in either render. The shadows are coloring correctly, and the Maya 2009 render looks much better than the 8.5 render, at this point. Still no light beams?

Grashock
07-20-2009, 08:00 PM
...in either render. The shadows are coloring correctly, and the Maya 2009 render looks much better than the 8.5 render, at this point. Still no light beams?

Yup, the 2009 looks better, and the shadows are correct, still no beams, I did get the parti_volume to render correctly in 2009 however, still no colored beams, but I'm much closer then I was. Here's the actual scene rendered with what I have at this stage. I still have some smoothing to do on some of the outer gears, and the clock facing, but so far, I'm pretty happy with it, just wish I could get those colored beams!

http://home.comcast.net/~lucas_moore/pwpimages/WIP04.jpg

Grashock
07-24-2009, 03:27 PM
So here's the current state of the project, I still haven't solved the problem of caustics and the light from the windows. I have considered using a particle system to try and bring the color through/transparent planes that work kinda like mirrors to bring shafts through, and some other optical type tricks. But I haven't settled on one I like so far. Needless to say, I intend to continue to work on the ideas that I started with this and will solve the issue eventually. I think the particle system is the most promising, but I'm still very new to dynamics and as such I'm not 100% on my ability to get the effect.

Any one have any ideas?

http://home.comcast.net/%7Elucas_moore/pwpimages/Stairway_Final.jpg

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