i am wondering how i can get the ray of light rendered in matra. basically a volumetric effect i guess.
thanks

Put an Atmosphere (Fog) Object in your scene.

In SHOPs, place a Lit Fog SHOP. Assign the Lit Fog to your Atmosphere Object.

In the SHOPs parameters, first set the Fog Density to a value of 0.2 to 0.4 to see the effect. The default value of 0.05 is a bit subtle for a first test.
Set the Max Steps to 100 to test out the effect when rendering. When you get the right look, up the steps until you get what you want. 100 or less may do and renders much faster. A bit of blur in the compositor hides a lot.

The Step Size can be left at default. This is a ray marching shader in that the ray marches along at discrete steps sampling all the lights every time, summing up the light values as it marches along. Decreasing the Step Size will slow down your render whereas increasing the Step makes the render go faster.

All your lights will now render as volumetric lights. If you set your lights to cast shadows, say fastShadow in the Shadow Shader field, then you will get the nice streaks in the lightbeams.

thanks old school
just what i wanted, but i did run into a problem. when i do have shadows enabled it doesn't seem to pick up the opacity or alpha of the object the light first hits. i'll keep trying, maybe i have done something incorrectly.
thanks again
b

ok, i'm slowly learning this. so opacity shouldn't have an effect but the alpha channel should be read, isn't this right? i just deleted some faces of the geo i'm using as an obstacle and it works great, but it would be good if it could read the alpha channel

I have no experience with atmospheres, but your problem sounds like your shadow shader is not set to “Filter Shadow”. Perhaps it is set to “Fast Shadow”, which won't lookup any transparency information, but will terminate already, if there is somewhere between the shaded point and the light-source a piece of geometry. The “Filter Shadow” is slower, because it will have to determine all intersections of the shadow-ray with the scene and evaluate the corresponding colors.

thanks frank, that was the problem.