Snow shader

[blackchicken]

Hello

Im new in shading and I have little problems there. There is a little cartoon model of large ICE. But some problems appears.

1, Why is some specular dots black? I multiply out specular with turb noise, but when I add it to lambert black spots apperas. How i could do nice shinny effect? As I explore basic shaders, when I want use texture it is multiplied by specular. Thats works. Where is problem?

2, How I could scale specular spots (turb noise) to a lot of realy small dots. Frequenci turb noise since 100 doesnt work.

3, Is there some pattern which could, with some trick, create pattern like on real picture of big snow? Like noisy boxy pattern as ice falling down? (I use 2 turb noise now)

Thanks a lot and sorry for that basic questions. B.C.

There Im now

Shader

Real pattern

Scene file

snow_shader_02.hip

[ikarus]

turbo noise outputs in the positive and negative range, clamp or fit the value coming out of that so its above zero, then you wont have a negative contribution to your color

[Erik_JE]

Or use the absolute value if you don't wanna care about fitting a certain range.

[Adam Ferestad]

Your shader also seems to be missing SSS contributions. Depending on various factors, ice becomes very translucent, especially where it is thin and around the edges of the block. I would think about doing some sort of volume vs. surface area check and where the SA is high compared to the volume, it becomes more translucent. IDK how this would be accomplished in Houdini though as I really haven't even started on Shaders at all. You might be able to calculate it in a SOP and pass the attribute to the shader. You might want to look at some more sources of ice in various lighting situations and see if you can notice something. Maybe some sort of SSS in conjunction with a volume shader would work out, no idea though. I may play with something if I get some free time on a weekend or something.

[blackchicken]

Thanks a lot

absolute is exactly what I need. Works ok. Have anybody any idea how to create proceduraly this kind of displacement like on picture? Thanks again for your help. B.C.

[Eitht]

Thanks a lot

absolute is exactly what I need. Works ok. Have anybody any idea how to create proceduraly this kind of displacement like on picture? Thanks again for your help. B.C.

Woo~ i look forward to seeing your completed shader.

Have you seen this?

Jwoelper shared his file in the thread.

http://forums.odforce.net/index.php?/topic/10798-procedural-stonesrocks/page__hl__jwoelper__fromsearch__1

eitht.

Edited July 18, 2011 by Eitht