Writing a shader

[lanchka]

Okay ,

I have a finished character in houdini.

I need to texture it.

I had this plan for the texture.

First , displacement using a cellular map.

Then I want to bump the displaced shader lightly with some noise.

Then ,the diffuse using the same cellular map for the diplacement with darker shades of green for the dark areas and light shades of green in the lighter areas.

Then a fresnel based falloff for a second skin like appearance.

I would also like to create a kind of slimy appearance with the falloff.

I have done something similar in max.But to do the same in houdini in vex seems out of reach .

Any tips on how to create this type of shader in vex or on any of the videos available at vislab which might help me would be appreciated.

Cheers

Lanchka

[TheUsualAlex]

Hi,

I believe there's a video tutorial on using the VOPs. Although VOPs may still require some basic knowledge of shader writings, but for the most part, it should be pretty accessible for your basic needs. I know there's are different noises in VOPs that's prebuilt for you such as Voronoi noise, etc. etc. Perhaps those should help you get started in playing with VOPs?

Cheers,

Alxe

[DaJuice]

Hey lanchka, do you mean something like this? Done in max a long time ago. And are you thinking of the cellular map in max, or the one in Houdini, because the two patterns are different. As far as I know the one in max isn't available in Houdini, but you can get close with Voronoi noise.

[lanchka]

Hey that looks pretty good.

How do u do that?Could u tell me?

Also I was looking for maybe a fresnel or atleast some normal falloff(something very pronounced).

[old school]

Here is what I call a gloop shader. It is written in vex and not vops right now. Does nice siimple cell noise. You can edit the code to do non-spherical cells like squares triangles, blotches, etc.

The bumps are more evenly distributed than in the example above but that is done simply by passing some low frequency noise to the cell bumps.

As for fresnel reflections, not currently in the shader but certainly doable.

gloop.hip.zip

[DaJuice]

Hey

If you look at this thread, stu has posted a VOPs falloff shader.

http://odforce.net/forum/index.php?showtopic=2405

I'll post up a VOPs example of the max shader or something similar later.

[DaJuice]

Ok, it's not a particularly great shader, but maybe it'll give you some ideas. If you have any questions let me know.

vornoi_cells.zip