I want to create a semi-transparent surface.
To do so i add a point SOP to a box. Then i add alpha.

but the geometry will still be the same as before and not become transparent.
If I render it, it also doesn't show transparency.

Why doesn't this work?
gr,
Esther

Have you tried using the standart Mantra Surface shader in SHOP and just play around with the Opacity values?

Johnny

Yes that works, but then i wonder what the alpha in a point SOP can be used for.
thanks already

I actually have no idea.. ops:

Never used it..

you can override any parameter on shader by adding an attribute of the same name and type to your geometry
so if you examine mantra surface, there is for example parameter called “opac_int” which is representing opacity intensity

so if you create new attribute on your geometry called “opac_int” set type to float (since the parameter on shader is float) and now the value of this attribute will be used for every point/face in the shader instead of user defined value

When I was fiddling around with trying to get transparency working the other day, someone mentioned that the default shader (plastic) completely ignores transparency, so that might be the source of the problem. The Mantra Surface Shader seemed to have the options I was looking for with reflections and refractions. It had some options for it to look at point attributes too, though I can't remember exactly what they were (my Houdini's currently blocked on a sequence that's slow to render).