solid transparent object with refrection?

User support for JPatch

solid transparent object with refrection?

Postby kl » Wed Jul 13, 2005 6:50 pm

Can I do it in JPatch?
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Postby dBug » Wed Jul 13, 2005 7:05 pm

I hope this is the answere for you otherwise i misunderstand your question.

Ofcourse you can do an solid object, the attributes you are talking about is render specific, the OpenGl preview in jPatch can not show refraction but a transparent surface is somewhat visible for you, if you use povray as an renderer of your object you have reflection/refraction and all other types of attributes for surface definition.

Probably most renders have them or else they are not useable at all.

/Henrik
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Postby sascha » Wed Jul 13, 2005 7:28 pm

Sure, just use the sliders in the material editor and watch the preview (it's a realtime raytraced sphere showing the material approximately like it would look in POV-Ray). For renderman, JPatch currently defaults to the "plastic" shader. For more complex textures you'll need to write your own shaders.

PS: The shaded view in JPatch does currently not use OpenGL, but a pure Java software renderer (that's why it's a bit slow). I'm working on true OpenGL support, so future versions should be a lot faster.
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Postby kl » Wed Jul 13, 2005 7:39 pm

But, how do fill up the patches? it is hollow.
The material only applies to the thin layer.
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Postby pndragon » Wed Jul 13, 2005 7:49 pm

You want a material as differentiated from a texture...

I don't think Jpatch creates solids filled with materials. Materials are left to the renderer, if they support them.

Jpatch can create the shape of the material...
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Postby sascha » Wed Jul 13, 2005 8:10 pm

Wait a moment: 3D programs work with surfaces. If the surface is completely opaque, it looks like a solid volume. Now let's look at semi-transparent surfaces: I think what you're looking for is what RenderMan calls "volume shader" (google for that subject).
Pov-Ray lets you define volumetric effects in the metrials interior block. Some things can be easily computed (like attenuation), others require complex computations (e.g. subsurface scattering - check POV-Rays media features). David also implemented SSS in Inyo, I think it will be available with one of the next JPatch releases.
Long story short, all volumetric effects belong to the rendering domain, not to modeling, so there is little JPatch can do. As far as the current material properties JPatch's material editor offers are concerned, there are no volumetric efects. But you can of course write custom textures (for POV-Ray) or shaders (for RenderMan).
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Postby kl » Wed Jul 13, 2005 8:27 pm

Understand.

just trying to make a realistic eyeball. I think it is good enough even it's hollow.

take a look, thanks!

Image
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Postby sascha » Wed Jul 13, 2005 8:43 pm

Wow, very nice head!

To make glass look solid, it's probably enough to set the "index of refraction" (ior).
Air is 1.0 (looks hollow like a soap bubble), water 1.3, glass 1.5, diamond 2.4,...
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Postby kl » Thu Jul 14, 2005 3:56 am

great info about the ior! thanks!

The head is the closeup of the same model with eyeballs.
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Postby sascha » Thu Jul 14, 2005 8:07 am

Ah, now I see. There was a typo in you initial post that made me think you were talking about "reflection", not "refraction"...
Sorry for the confusion.

Refraction should work out of the box with POV-Ray and Inyo. For RenderMan, you'd have to use a custom shader and pass the requireded attributes over.
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