Hi, I just downloaded the latest 2.7b.
For some reason, I’m unable to get decent caustics.
At 500 samples, I’m getting very little of the light and the color of the glass on Suzanne to really come through and hit the plane beneath.
Can anyone help me? Please let me know what I’m doing incorrectly.
Thanks.
That “filter glossy” “No caustic” “Clamp Direct” “CLamp indirect” must be eliminated from GUI and every “tutorials” ASAP.
@jasonhan, reset all that properties above to defaults (0.0) and NEVER touch them despite any tutorial claims that they magically “remove noise”.
BTW, sun lamp never give you caustic passing glass/mirror with roughness=0, as you maybe expect, as you cannot connect path from camera->flat floor-> arbitrary direction. You need mesh lamp, or contrast background for that, but expect very long render time. So, even if you make changes as i note above, you get only very subtlecaustic from dull flat background.
Here is example, i remove background, change light to point, and use experimental bidirectional render (just to illustrate prolem). You can try same by replacing lamp py tiny mesh lamp or very contrast background environment map.
To elaborate and add what I did to get caustics with your scene:
Disable clamping (indirect): Basically caustics are brighter, concentrated areas of light, and clamping the indirect lighting to 1 basically clamps out the caustics.
Filter Glossy at 0.2: Basically it blurs the caustics, which are made from small sharp light paths, and again hiding the caustics.
Sun size: The size of 0.1 makes the sun quite large, and stops it producing sharp shadows, or caustics. Reducing the size from 0.1 to 0.01 increases the sharpness of any produced caustics, but makes it a lot harder for Cycles to randomly hit a caustic path.
Samples: 500 samples isn’t anywhere near enough to get a good render, the example below has 20,000 samples.
I also disabled the world lamp, to focus on the caustics specifically.
Took 14min 22sec on 2x GTX 970’s
1 Min CPU render with LuxRender, which is a bidirectional path tracer that generally works best in this situations (except some kinds of photon mapping if tweaked right)