Hi.
I’m trying to match the reflected light (circled in green) in the photo attached. It is not showing up in the rendered version. Reflected caustics is turned on. I tried using actual caustics but it didn’t seem to change anything either. I’ve even tried putting a mirror surface there but it still doesn’t show up.
Any ideas as to what could be causing this to fail?
Justin
Would it be possible to send the scene file to support@chaosgroup.com so we can check it here?
Sent 5 days ago. Any update on this?
Hi Justin,
Apologies for the delay in reply!
Please enable the Caustics in the GI tab and move the sun target more or less here:
http://ftp.chaosgroup.com/support/2019-02-26\_15-13-42.png
The Photon emit radius value should be edited too (for example 10000mm starts showing some results on the wall).
This is the result I get after editing the mentioned above settings:
http://ftp.chaosgroup.com/support/2019-02-26\_15-24-50.png
*You can use the Caustics multiplier to make the reflections more pronounced
Please let me know in case you have additional questions.
Thanks Kristina!
It seems to be working for me according to your directions.
One question though. Does the photon map have to be calculated for each frame of the animation (moving camera only)?
you can save the calculated map out, and set the mode to “from file” instead of “new map”, just look under the caustics tab…
Yes I’m aware of that mode. So does this mean that the caustics are computed for the scene, not just for the camera?
If you don’t move the sun’s position it should be fine with a saved photon map.
So does vray have to reload the caustics map for each subsequent frame? I’m finding the file size is between 12-15Gb for a decent quality caustics solution. The load time is significant.
Yes. 15 GB sounds unnecessary large. I’ll ask the support to check the scene.
does anyone still uses caustics ?..it is such a pain to config, and slow…
For a clean solution I had to increase the sun’s caustics subdivs to 15000. This increases the file size significantly.
You’re right. It is a pain. And quite un-intuitive. Vlado did mention something in this post about making caustics a bit easier for update 2. Hope they work on making it faster too.
It can take a few minutes to pre-calculate, but it’s not really much of a pain to setup. I usually run it as a separate pass, so that if I need to adjust it I don’t need to re-render the entire scene again.
I had forgotten this technique, which just saved me a big headache on a project, so thanks for linking it here so long ago 
This should really be added to the docs as an alternative technique, given that it is so useful.
As a side note the docs entry on caustics seems to be many many years out of date and contains errors and omissions.
