"Chris Friedl" <cfr### [at] bigpondnetau> wrote in message
news:3d0ec37a@news.povray.org...
> Just getting into POV now. I wanted to create "visible" light rays
streaming
> from an object

Welcome aboard, Chris.

Yep, just by coincidence and chance I made that scene for the Insert Menu.
The real difficulty in such a thing as media scattering is getting a good
brightness of the light beams while also not darkening everything else out.
Using media within a certain constrained volume is often best for what you
want to do, using a fading light source too, that way the only affected area
is nearby and easier to adjust.

Okay, about the pulsating light. If you want the entire ray beaming object
to pulse that's simply a case of changing the lights color from a small
value to large value and back again. If you'd like the individual rays to
change the thing to do is manipulate the objects texture via filter or
transmit in a pigment pattern. Both would use the 'clock' keyword
multiplied, or whatever, with the float values used in those. Chris Colefax
has a Clock Modifier macro (or the include) which is perfect for this
because it has various ways of increasing and decreasing values over time.
If you're not too adept or quick at learning that, you can just try
something like following for a pulsing light color:

sin(clock*pi)*TheFloatOrVector // use your own color float or vector

Same could be put in as the transparency value instead, for the color map
for example. You need to multiply the clock in that sin() by double number
of times you want it to pulsate. So 8*clock equals 4 pulses.

I have an example made up if you'd like it. Thought I'd ask first if you
might want to try something yourself instead. In the meantime you can always
check out the demo scenes (Scenes\Interior\Media) and that part I did with
the windowed room which is in the Insert Menu folder (CSG_material.pov, last
part).

bob h

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