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Sneak Preview: sIBL 4 Maya V0.16 (Read 12408 times)
volXen
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Sneak Preview: sIBL 4 Maya V0.16
04/22/08 at 23:59:28
 
Hello Everyone!
Thanks to Zap Andersonīs Production Shaders and Matt Estela pointing me to this solution sIBL can finally setup scenes that render correctly with background, reflection and environment lighting in Maya 2008. This update also validates the content of the sIBL-folder which gave some people errors when using older versions and thanks to mantered the glow on mia_materials doesnīt explode any more! I will update the download links to point the new version next weekend but I would like to encourage everyone to grab my current work in progress - version of sIBL 0.16a now from this link and give it a try, any feedback as soon as possible is highly appreciated!
So if you got any ideas how to improve the script or it doesnīt work as expected... let me know!

Download-Link: http://www.renderwahnsinn.de/sIBL_16.zip

Cheers,
V
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« Last Edit: 06/10/08 at 06:04:21 by Blochi »  
 
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volXen
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #1 - 04/28/08 at 22:12:12
 
I made some minor adjustments to Version 0.16 and updated the official download link http://www.renderwahnsinn.de/sIBL.zip. The previous version is still available for download from http://www.renderwahnsinn.de/sIBL_15.zip. ;

V
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Tripuco
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #2 - 04/30/08 at 08:27:06
 
Hello volXen,

the rayswitch version works fine, but the bg texture should also be conected to the "refraction" and "transparency" slot of the rayswitch shader, right? Easy to fix, maybe for the next version.  Wink

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volXen
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #3 - 04/30/08 at 11:18:15
 
Hi Tripuco!
Do you think so? I assumed BG should be nothing but a reference by definition... and I think thatīs how it workes in the other loaders, too. But if there is demand for this functionality I can include optional parameters in the future.

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Blochi
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Hollywood
Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #4 - 04/30/08 at 16:23:12
 
Actually, I am connecting the the Reflection image to Transparency. Ensures a punching-through effect, great slightly transparent objects or SSS .

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Adam Gravois
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #5 - 07/17/08 at 00:04:22
 
What a great tool sIBLedit and sIBL 4 Maya are! Thanks for making them!

I have found a minor bug in 0.16a that I don't see mentioned elsewhere in the forums:

Create bkgd/env/refl maps with the ibl node, and no rayswitch:
mentalrayibl node has "Primary Visibility", "Visible as Environment", "Visible In Secondary Reflections" set to ON. Since this node is only for lighting, these should probably be OFF.
refSphere_x node has "miFinalGatherCast" and "miFinalGatherReceive" set to ON. Since this node shouldn't contribute to FG, those should probably be OFF as well.

I think there is also an inconsistency between the refSphere/bgSphere and the IBL. The IBL appears to be rotated ~80 degrees around Y away from the refSphere. This will give incorrect results. I haven't experimented a lot to verify this bug yet, because while I was investigating it, I had a better idea:

Why not use mip_rayswitch in the mentalrayibl node for Final Gather, Relfection and Background? One of the things that was bugging me about the ibl/bgSphere was the discrepancy between the infinite ibl sphere and the finite bgSphere. They look different, and the infinite sphere seems to give a more accurate view of the bg. I can't have an infinitely big polygon sphere, and very large spheres slow down final gather (or so I've been led to believe).

mentalrayIbl doesn't seem to like being fed the mip_raywitch result directly. So, I experimented a bit, and figured out that if mip_rayswitch goes into layeredTexture, layeredTexture can be fed into the "color" attribute of the mentalrayIbl node (which itself has been swtiched from type "Image File" to type "Texture" of course). This appears to work perfectly: now reflection, fg and background are cast as if from an infinite distance. What a awesome tool mip_rayswitch is!

Hopefully there's a more elegant way to do this than passing it through the layeredTexture node, but that works for now.

Thanks Blochi & volXen & everyone else for maintaining this resource. I ordered Blochi's book yesterday and can't wait to sink my teeth into it.
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Blochi
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Hollywood
Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #6 - 07/17/08 at 01:08:16
 
I can't comment on Hypershade voodoo, but the generic hack for getting a clean distortion-less render from the BG sphere is to place it at the camera position. Then size doesn't matter anymore. You could even get tricky with a position constraint, I guess...
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volXen
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #7 - 07/17/08 at 03:30:29
 
Thanks for your ideas and observations, Adam!

Iīll try to fix those bugs you mentioned ... and probably include a new
parameter for using rayswith with the ibl node.

V
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Adam Gravois
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #8 - 07/17/08 at 15:07:10
 
Quote:
the generic hack for getting a clean distortion-less render from the BG sphere is to place it at the camera position.


A-ha! Thanks for the tip.
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Adam Gravois
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #9 - 07/17/08 at 16:38:49
 
volXen-

re. the inconsistency between the refSphere/bgSphere and the IBL, the problem is Maya, not your plugin. Wink Here's why:

When you adjust the subdivisions Axis for the polySphere shape, the UVs slide around the surface! Try it sometime. One edgeloop remains stationary in worldspace while all the other edgeloops move clockwise to create room for new loops, but the UV map originates at the "last" edgeloop and propagates counterclockwise. See attached.

Hmpf! Perhaps it's best to stick with either all ibl sphere or all polysphere to maintain alignment.
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polySphere_UV_sliding.jpg (Attachment deleted)
 
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Blochi
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Hollywood
Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #10 - 07/17/08 at 16:48:08
 
Should have posted this image from the Handbook page 321, because it sort of makes the point clear. BTW - if you have other geometry in the scene, and your camera doesn't move (only rotates), you can map the panorama with a spherical projection centered on the camera position and it will match. Good for the ground or major buildings....

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12_Mustang_ball-projection.jpg (Attachment deleted)
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Blochi
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Hollywood
Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #11 - 07/17/08 at 16:51:50
 
Ahhh ... That Maya UV projection looks messed up.
Agree, a fixed polysphere would be the best. If you would like, I can convert the polysphere my Lightwave plugin uses. Sounds strange, but this is a really special sphere, because it also has UV coordinates for a panos in Angular (Lightprobe) format. Took me quite a while to make this model...

Blochi
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Adam Gravois
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #12 - 07/18/08 at 00:10:15
 
That is helpful, thanks. Is there more in the book about camera placement when shooting HDRs? (the cheap shipping from Amazon is mighty slow and now I'm wishing I paid for faster shipping!) I am curious what the best practice is... place the mirror ball where the 3d camera will be, or where the CG subject will be? And how do you handle CG camera moves that are more complex than a nodal pan? Can it be done with a single panorama, or do you blend somehow between different ones? Are these subjects addressed in the book? Perhaps this question is best asked somewhere other than an obscure corner of the "Software Plugins Discussion Forum"? Wink
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Blochi
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Hollywood
Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #13 - 07/18/08 at 02:52:18
 
Well, technically this is what the Virtual Light section is for. But I keep moderation to a minimum, and after all this is a fact mentioned in the book... Wink There are more tips in there like this. The HDRI should be taken from where the object is, and using the pano as a background is really just some sort of bandaid. In real world scenarios, you'd have a background plate, or you would shoot shoot a background photograph...

Blochi
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Adam Gravois
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Re: Sneak Preview: sIBL 4 Maya V0.16
Reply #14 - 07/18/08 at 15:25:36
 
Thanks, that makes sense.
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