Hi all,

How did you start with shader in Houdini ? I am stuck ! Example, i want to implement a basic phong shader in Vop, how can i do that ? I came from XSI, and i want to do something like,…a shader that when the normal point directly to the camera, the surface will be transparent, the far away from the camera the normal point to, the surface become less transparent, how…? Really messed up.

…I read some renderman book, let say i can translate renderman code to mantra, but from the code i want to build the same shader using the Vex network builder instead of compiling the code,….. no clue ..

And i cannot find some example in the document, i dont know why the document have nothing about building shader in Vex Network builder, or i just blind :shock:

I found a useful tutorial through odforce some time ago.
Try looking there or try to google “Writing a VEX shader for Houdini”.

Hi mathmad. A really good way to learn VEX/VOPs is to look at other people's code/networks and study how things work. The material gallery shaders are a good (yet complicated) place to start. Also to that end I attached a commented file that I think does the things you were describing that you could maybe take a look at.

I think once you spend a little time getting comfortable with VOPs you'll find that its no more difficult to work with than the XSI shading environment.

Good luck dude!

I really appreciated brianBurke and Tranguz. I have just found this link http://www.andynicholas.com/?p=19 [andynicholas.com] , it look good.
I have used a lot of 3d software, but the only one that i can use the material system quite easy is maya. I am still stuck with XSI shader too. I think the way we build shader in a network style like houdini will be very straighforward, i just didnt get it . Waiting for cmivfx release a training course about that :twisted:. Right now i have finished some training from cmivfx, i am really hunger to make something like a burning fire or a particle effect but stuck right at the shader !

Thanks again, i will post some question in the future.

The shader networks are very very similar to XSI. One thing that may throw you off at first are the parameter nodes because they are everywhere and there is no such thing in softimage. I think if you familiarize yourself with them the rest will look very xsi-ish.

Only better, of course.

Yeah, you are right Soothsayer, the parameter nodes are everywhere and i dont really know what it is used for ! Like i make a simple Phong shader with allow user to input the diffuse color. I make a parameter node and name it Diffuse color and then plug it to the diffuse channel of the light model node, then plug the light mode node output to the color of the output node. Thats all i know !
I created some material and tried to explore the way it work,….i gave up ! the parameter node are every where !
Do you know where can i find some easy to understand, simple shader network ? Something like a basic glass material or some volume material ? :evil: I guess no cause the build in material are too complicate enough

And one more thing, is the volume material and the normal surface material the same ? Because i explore the volume material network and i dont know where the shader get information about the volume attribute like density, heat…from !

Men, i dont want to give up :twisted:

I made you a simple shader. I made 2 parameters. One called “Use Point Color test” and one called “Specular Intensity test”.

If you dive inside you see a surface color shader that creates surface color. It has a parameter that you can use to toggle point colors which are added as a SOP in the sphere object.

Theres also a Specular shader, with a parameter to change intensity.

On the vopsurface1 node parameter window you can see the parameters I added.

Sometimes Renderview doesn't update changes properly, so don't despair when it doesnt seem to work occasionaly.

mathmad
guess no cause the build in material are too complicate enough

The built-in shaders are only complicated because they try to provide a lot of options.
When you create your own materials you can make them much much simpler, and only build the stuff that you need, instead of every parameter under the sun.