VRay caustics look bad despite high settings

[VRAYCaustic]

The caustics look bad despite my high settings. The caustics were produced by a sun with this settings:

Photon Radius: 50
Photon Subdivs: 500

Caustic Mult: 1
Caustic Subdivs: 8000

General Caustic Settings:

Multi: 2.0
Search Distance: 1.0
Max Photons: 120
Max Density: 0.0

How can make the caustic sharper and less splotchy?

[bdancer]

Could you post the whole screenshot and explain what result do you want to achieve?

[VRAYCaustic]

explain what result do you want to achieve?

I want to achieve sharper and less splotchy caustics, like here: http://docs.chaosgroup.com/download/...1663000&api=v2

[yolov]

In general, the smaller the search distance and the fewer the max photons, the sharper the caustics. You can start by lowering "max photons".
Since the sun is your only source of photons, you can also lower it's photon radius so it just covers the window.
If things start to get really slow, you can use object properties to set which objects should not receive caustics.
That's a very vague description, I know, but it will also depend on your scene units - it might turn out that you need less than 1 for search distance.
Give those a try and let us know how it turns out.

[VRAYCaustic]

Thanks for your answer, i rendered the image again two times. So the first one i reduced the amount of max photons to 60:



In the second image i also reduced the search distance to 0.67:



But it doesn't look like it changed anything. Besides the bad caustics: does anybody know where these horrible black borders around the window come from?

[yolov]

It would be easier to be able to look at the scene. Can you send it over ?
The black borders could be from the GI, but I'll have to take a look.

[VRAYCaustic]

http://www.pasteall.org/blend/41086

[yolov]

Thanks, I'll have a look and I'll get back to you.

[VRAYCaustic]

Thank you very much!

[VRAYCaustic]

So do you have any news for me?

[bdancer]

Here is my result (scene):

Render time is about 5 min so it's pretty noisy, and I've changed scene a bit...

[VRAYCaustic]

Wow this looks totally different than my scene, in a good way! Could you give me your render and caustic settings? How could i make the caustics sharper?

[bdancer]

VRAYCaustic, there is a link to the scene file in the post, you could check settings there.

[VRAYCaustic]

How did you do the material? If i take a look in the material preview window it looks like this, why is it so black?

[bdancer]

Fog color depends on object thickness, thats why it looks like that for the preview sphere.