BDPathTracing Caustics, can it be done

[anchovy]

Vlado-

Ive tried a couple pool caustics tests and I know the BDPT has a few issues right now but should i be able to get something like this? So far no real success with my attempts... I should say Ive been trying with the Vray sun and sky. I have been able to get some ok looking ones in my cornell box setup.



Thanks!

-Michael

[vlado]

If you are looking at the caustics through the water itself, then you will need to make the water material to have slightly glossy refraction. Even then, the result will not be any cleaner than regular path tracing. Bidirectional path tracing only works for directly visible caustics, whereas caustics through glass and mirrors are essentially equivalent to what you'd get with regular path tracing. If you need to look at the caustics through the water, then regular photon-mapped caustics will work better - or you can fake it as in the image above.

Best regards,
Vlado

[anchovy]

--== Anything that works will be used in progressively more challenging applications until it fails. ==--

Vlado-

As your tagline says Ill keep pushing

-Michael

[Javadevil]

I found I couldn't get the water caustics from the sun, but could using an emitter.

[vlado]

You will need to set the photon emission beam properly (the green cylinder that represents the V-Ray sun in the viewport). Photons are only shot within that beam.

Best regards,
Vlado

[Javadevil]

Here's a test for pool caustics, you can see caustics are generated through the teapots but not through the water.
File attached.



https://www.dropbox.com/s/aw3k1mcq4f...test.01.max.7z

[vlado]

Here's a test for pool caustics, you can see caustics are generated through the teapots

I can see the caustics directly on the plane, but there are no caustics inside the teapots.

Best regards,
Vlado

[Javadevil]

The caustics I want to see is the bottom of the pool, through the water.

[vlado]

Like I explained before, this cannot be done with the bidirectional path tracer (for the moment). You will have to use regular photon-mapped caustics.

Best regards,
Vlado