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DrStrik9
07-03-2009, 07:46 PM
As a personal project, I've been trying to texture this cartoon fish model so its internal organs are visible through its skin.

Today I pulled out FPrime: I haven't used it much recently -- until the upcoming 9.6.1 Mac hotfix, it can't address all the Mac cores so it's kind of slow -- and low and behold, FPrime can see mapped color and diffuse artwork through the Simple Skin material node, and Lightwave's renderer CAN'T.

In the attached example, note specifically the artwork mapped to the inner organs, which FPrime renders, but LW doesn't. (I've tried the Classic Cam and the Perspective Cam with the exact same results, except Perspective Cam is a lot slower). There's something different about the transparent parts too, but Worley says it's a limitation of the LW SDK ...

Is this a LW bug? Or just something special about FPrime? Seems like LW should be able to render it if FPrime can, right?

geo_n
07-03-2009, 07:50 PM
As a personal project, I've been trying to texture this cartoon fish model so its internal organs are visible through its skin.

Today I pulled out FPrime: I haven't used it much recently -- until the upcoming 9.6.1 Mac hotfix, it can't address all the Mac cores so it's kind of slow -- and low and behold, FPrime can see mapped color and diffuse artwork through the Simple Skin material node, and Lightwave's renderer CAN'T.

In the attached example, note specifically the artwork mapped to the inner organs, which FPrime renders, but LW doesn't. (I've tried the Classic Cam and the Perspective Cam with the exact same results, except Perspective Cam is a lot slower). There's something different about the transparent parts too, but Worley says it's a limitation of the LW SDK ...

Is this a LW bug? Or just something special about FPrime? Seems like LW should be able to render it if FPrime can, right?

up ray recursion?

DrStrik9
07-03-2009, 07:59 PM
Tried that ... It's already at 16 ...

Matt
07-04-2009, 05:41 AM
Are you using GI? If so, what are your settings?

DrStrik9
07-05-2009, 09:02 AM
No GI, just three area lights. The top one is very orange, the warm side lower one is almost red, and the back light is very purple. The light color has a lot to do with the look of this. On the purple side, the inner art doesn't show, but I think it's because of the light color.

The three layer nodes are for a UV map.

IMI
07-05-2009, 11:42 AM
I've been trying to figure this out...

I think what's happening is it's actually FPrime which is rendering it incorrectly. You say it's "through the Simple Skin material node". So I think that it looks more like what you want, because FPrime isn't seeing the Simple Skin node correctly, like it's not taking its depth or double-sided-ness into account.

Without having the object and scene, it's hard to tell, but do you have the V stack on or off? Double sided? Might want to mess with the refraction settings and epidermis/subdermis distance, or even use SSS nodes instead of the Simple Skin material.

What you want though is to have a transparent outer skin, but to have SSS at the same time. That seems like it would be pretty hard to pull off, since SSS has to have some depth and opacity to work with, while too much opacity will obscure your inner fishy. Wow, that last line just sounds weird. ;)

So since FPrime can't render most (or all) material nodes correctly, it's giving the illusion that it is, but it's an error. I think what you need to do is work out a balance between opacity, translucency, and SSS to get what you're looking for.

DrStrik9
07-05-2009, 06:04 PM
IMI, thanks for that perspective. Being the proverbial node-noob still, I appreciate any illumination on how to approach nodes that I can get! :-)

According to Worley, FPrime now renders all the nodes correctly, with the exception of some aspects of transparency -- so it may very well be the transparency portion of Simple Skin that allows FPrime to "see" the mapped art through a polygonal layer of Simple Skin, when it shouldn't. It is true that the two renders (LW and FPrime) do look a bit different in general.

I'll give the SSS node a try and see where I bump my head ...

One thing that would really make this work well would be an ability to somehow blur the inner geometry, based on distance from the outer surface and the camera. Right now, all the inner objects are sharp, as if the fish was made of water. If it was flesh or anything thicker than water, the inner geometry would be depth-blurred, in varying degrees. That will probably require me to get my phd in nodes. LOL How DO nodes and expressions work together? <splat> my brain just exploded.

DrStrik9
07-06-2009, 05:10 PM
I've had some success using SSS instead of the Simple Skin material node. So I'm taking this over to an existing thread under Work-In-Progress: http://www.newtek.com/forums/showthread.php?t=99922

toby
07-06-2009, 05:52 PM
Refraction blur would blur any inner geometry, and make textures visible, not sure if that's a part of any nodes, but I'd think it was.