Caustics?…

[Brian Jones]

can you post the scene? If the angles are not right the caustics can be on but you see nothing. Otherwise what are the settings? ramp the strength way up to see if anything shows. And why volume caustics, with reflections only surface should be necessary I think.

[Adam Trachtenberg]

I think you’re misunderstanding volume caustics. That refers to the focusing of light as it passes through a refractive object (think magnifying glass). AFAIK there is no way to get caustics to render volumetric light.

[Alex Reardon]

Adam,
Thank you for that.
In that case, what would you suggest to create a beam of light bouncing back from a mirror? I’m in the middle of a production design for an arena tour where full colour lasers are to be used both reflecting off moving mirrors, and refracting through rotating lenses.
I have been able to fake it by using a very narrow cylinder as the beam and adding colour and glow, but I’m curious to know how to do it properly. Its all-too-easy to use the quick fix and become lazy….

[Adam Trachtenberg]

In this case I think you’re doing it the only way it can be done. None of the volumetric effects appear to see caustic light.

[Alex Reardon]

Hmmm, so there’s no way for a spot light to actually bounce off a mirror? Surely not.
Of course as soon as someone says, “it can’t be done”….. 🙂

[Adam Trachtenberg]

The light itself bounces but not the volumetric beam. I’ve tried to make it work with pyrocluster, environmental fog, other volume lights … even DPIT Effex smoke. No luck.

[Alex Reardon]

To quote Sir Winston Churchill: “Crap”.
Thank you anyway though. I shall continue fudging it.

One other question;
Is there some way to give attribute different types of spline to indevidual points within a spline? Often I’m trying to model something that starts with a curve, then hits a hard angel, then a curve etc.

Thanks again for being such an incredible resource.

[Adam Trachtenberg]

My pleasure. I never thought to check before you asked.

Regarding spline points (assuming bezier spline), when you select one and right click you get the option to covnert between hard and soft interpolation. Basically all that does is move the tangent handles to the same position as the point (for hard interpolation). If you shift-drag the handles it breaks tangency so you can make sharp turns. If you double-click on the point itself it brings up a dialogue where you can set values numerically.

hth

[Alex Reardon]

Oh FINALLY!
I knew it had to be in there somewhere.

Once again, thank you sir!