Question relating mr - Volume Caustics

[Chris Hoffmann]

Hi!

I’m Chris, new to the forums. :D

A couple of weeks ago I tried to get some wonderful Volume Caustics but unfortunately to date without results. (Max 2010 Des.)

I tried to adapt some example files from Jeff Patton as well as
other Files people shared but without success.
I adapted nearly everything from the Files in which the Effect is working. The render settings, material configurations, units set-up, mesh settings etc..

I’ve created a Box with one face deleted and an applied shell-modifier to get an Environment for the Volume-Effect.

In the Camera-Shader I put an parti-volume shader.
I created a Spotlight pointing from inside the box to the
ground of it.

I put a plane in front of it making it a Photon-Catcher with
a mental ray material applied. (transmat-photon, parti-volume, parti photon-volume. I left the other Slots empty (Hull-Object).

Now the usual Sphere with an a&d material applied.
(slightly coloured tint via the refraction distance colour)
I’m pretty sure the settings are right here. ;)

Now when I activate and configure caustics in the render settings I get some caustics but not in the volume. The »shadow« in the media aren’t coloured as well. Now when I activate GI and deactivate Caustics I get an coloured ray as it travels through the sphere.
I tried to put a metal material »in the rays« - well I got caustics on the ceiling but no Volume Caustics from the metal plate to the ceiling.

By now I have absolutely no idea what’s wrong with the scene.
Everything is nearly 100% identical to for example Jeff Pattons scenes.

Has anyone similar problems with the effect?

Kind regards,
Chris

[Chris Hoffmann]

Here’s a small update on the volume caustics issue:

I recreated a similar scene in 3ds Max 2009 which initially didn’t work as well with the same settings.
I then changed my photometric light source with a simple mr-light and tadaaa, suddenly there were caustics in the medium.
(kind of strange cause I formerly haven't used any completely other settings of light energy /unit scale etc..) Anyway.

I tried to recreate the scene again via 3ds Max 2009 AND 2010 with the mr-lightsource, same settings, same unit scale but it doesn't work again.

I'll keep you up-to-date.

Kind regards,
Chris


Update:

I finally managed to fix the problem via a much more logical way. (The way I did is truely much more simple than anything I ever read about Volume Caustics via mr.)

I'll keep you up to date with explanations if you're interested!?

Chris.