Lighting Challenge #3: Hairy Hare

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  04 April 2006
thanks mate... ya know.. it's really easy to get hair of a ball, but applying to this darn bunny is just a pain in the ass =)
 
  04 April 2006
Thanks jeremy!
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Nino Del Padre
Del Padre Visual Productions, Inc.
www.delpadre.com
 
  04 April 2006
Iím really interested to see what I can do with this challenge. Never really had a chance to light scenes with hair/fur so this should be interesting. Since XSI does have any real presets for fur of any kind I am spending some time with a fur ball getting reasonable look I can go with for the bunny as well as exploring how it would react to light and shadow.

C&C are always welcomed.
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File Type: jpg Hairball_3pl_test1.jpg (19.3 KB, 239 views)
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Cheers!
 
  04 April 2006
Posted for C&C. Lightwave with SASLite for fur and grass. Because of this, lighting was restricted to three spotlights with shadowmaps (no raytracing), and no G.I. Minor c.c. and sky in post. Great challenge!

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  04 April 2006
Quote: ...but applying to this darn bunny is just a pain in the ass =)


that being said...it really is a pain.. its been almost 2 weeks since i downloaded the scene. and tried applying the fur on the hare..i've never been lucky enough to get what i want..painting maya fur is harder than i thought it would be..so i resorted in using different 3D packages and plugins. unfortunately, that didnt help...but i'd still try to make it work..

anyway..nice work moosedog..

posting to subscribe...=P
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  04 April 2006
Originally Posted by herbertagudera: i've never been lucky enough to get what i want..painting maya fur is harder than i thought it would be..so i resorted in using different 3D packages and plugins. unfortunately, that didnt help...but i'd still try to make it work..


If anyone wants to post some WIP or test images, or ask specific questions, I'm sure you could get some help. Especially if you happen to be using Maya Fur, that's been used on this model before...

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2006
Done further R&D on the shader, still with a fur ball. Made a run through of different coloring techniques. Iím thinking of controlling the color placement based o vertex color info; this would avoid the need to unwrap and add an extra texture map. I also added secondary hair emitter for coarse hair strands. Next step would be to break into passes and go through the comp process involved. Then comes the rabbit itself.
C&C are welcomed.
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File Type: jpg Hairball_3pl_colors3.jpg (22.9 KB, 145 views)
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Cheers!
 
  04 April 2006
Cool

Here's another try.... better.... but still needs work.


It's mr hair primitives for grass and rabbit fur.

The AEC "foliage" plugin for max made the shrubbery (that plugin is pretty cool, totally procedural fractally based trees!)

All lit by a single area light (sun) and FG (from HDR sky).
(I.e. 100% real physics and GI, no oldschool "bounce light" mumbo-jumbo here )
All straight from the render, no "comp" work or post touchups.

One "trick" I tried is that the wabbit doesn't actually have all that much fur... it's actually an anisotropic shader on the rabbit "skin" itself to "simulate" a basic fur, and the added actual hairs is more to make it "read" as mor "fur" than there really are...

/Z
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  04 April 2006
Here is an update, a little better but it still needs a lot of work. I was able to get better results with the Nurbs model. Let me know what you think.

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Nino Del Padre
Del Padre Visual Productions, Inc.
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  04 April 2006
ShadowM8 -

Good start. Try to cover the skin completely. Test what you can do to increase coverage without an insane hair count, like maybe the thickness can go higher on each hair, longer fur length, more bending/curling, tips can taper out by reducing tip opacity instead of just thickness, or just better fur shadowing to darken the skin.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2006
Thanks for the feedback Jeremy.
I will try to increase my fur/surface coverage via the techniques you suggested.

Right now the color of my sphere (skin) is fairly light as is the real skin. But from some of my reading about hair rendering techniques it seems common for artists to choose a skin color very similar to the final look of the hair they are going for. Which tends to allow for lesser densities of hair. I am not sure if this is a right approach or not...

I've done further R&D with color. The use of vertex_rgba to interactively paint color variation works great. I am however finding it difficult to control the color values itself as it gets adjusted when it is actually rendered on hair, so I am going to need to allocate some time for color correction for the bunny.

I am not really happy with how much control I have over specular behavior, especially when it comes to the overall body of hair and not the individual strands. I would like to have my spec as a separate pass to have an extra level of control in comp but that has proven a bit of a challenge.

Cheers.
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  04 April 2006
delpadre -

Glad if its working better. The image still looks flat, as if it is lacking is shading and shadowing. Try rendering it lit by one spotlight somewhere above the rabbit, so you can clearly see that the rabbit and the fur are casting shadows onto themselves and onto the grass.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2006
Here is where I left off last night, trying to get the ear looking better and the fur less bushy. I also tried adding some whiskers but as you can see they donít really look like whiskers yet! I will try moving the spotlight from behind the camera to above the rabbit like you suggested. I was trying to go for that Flash photography look like Zaps render but I guess I donít know how to do it or itís not working for this image.

Thanks for your help and comments.

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Nino Del Padre
Del Padre Visual Productions, Inc.
www.delpadre.com
 
  04 April 2006
Originally Posted by ShadowM8: from some of my reading about hair rendering techniques it seems common for artists to choose a skin color very similar to the final look of the hair they are going for. Which tends to allow for lesser densities of hair. I am not sure if this is a right approach or not...


There's a place for shading/texturing the surface under the fur to look like fur. Imagine if you had a really large terrain and in wide-shots you didn't see every blade of grass, you'd want a flat grass texture over parts of it, and only turfs of grass near the peaks and edges and in the foreground. The same goes with distant characters.

But I think for a close-up of a rabbit, the rabbit should be covered with real fur. Texture mapped surfaces, or even textures on little cards as in Ice Age 1, would not hold up well enough in close-up, and wouldn't even cast correct shadows. Inclose-ups, in areas where skin would be covered with a thick pelt of fur in real life, it comes out looking wrong if you see the original outline of the rabbit surfaces.

MasterZap was just doing interesting tests along those lines, and you can see the results: Even though highlights on fur have an anisotropic quality to them when you put enough hairs together, giving the rabbit a shiny anisotropic shader doesn't make him look good with thinning hair.

( Maybe some really clever shader development could change my mind about this, if it did the self-occlusion from a polynomial texture map based on real rabbit fur and some kind of edge mapping in the render and the shadow maps, but I haven't seen it yet. What I've seen, in my limited experience with hair and fur, is that only real strands of fur that can individually cast and receive shadows end up looking like fur in a close-up. )

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2006
Originally Posted by delpadre: Here is where I left off last night, trying to get the ear looking better and the fur less bushy. I also tried adding some whiskers but as you can see they donít really look like whiskers yet! I will try moving the spotlight from behind the camera to above the rabbit like you suggested. I was trying to go for that Flash photography look like Zaps render but I guess I donít know how to do it or itís not working for this image.

Thanks for your help and comments.


If you want a flash photography look that's great, but no matter what angle your light comes from do some tests to make 100% sure your shadowing is working. I don't see the shadowing, that's all I meant, it looks like shadowing is turned off or not working.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
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