Bathtub water caustics?

[jophus14]

I am hoping someone in here could give me some insight on how to get a slight caustics effect on my walls from bathtub water. I read through some tutorials but most of them were from wine glasses and other glass objects, but not for a water plane. Thanks.

[TheAllusionisst]

Maybe this little 'Caustic Generator' utility and the information here will help you out:

 

http://www.lysator.liu.se/~kand/caustics/

[shaneis]

...I read through some tutorials but most of them were from wine glasses and other glass objects, but not for a water plane...

 

If you're using caustics through a plane for water, you'll need to add a slight ripple to the plane. That way, the photons will penetrate the surface at different angles and divert their path irregularly.

 

In the examples below, both are rendered using exactly the same settings. The first uses a perfectly flat plane and my ducks were more interested in myself and the camera. The second uses the same plane with a rippled displacement and my ducks found the caustic effects quite interesting

 

Both images have the same render times.

[jophus14]

Maybe this little 'Caustic Generator' utility and the information here will help you out:/QUOTE]

 

That's a pretty sweet generator. Thanks for the post. I'm going to look into that.

 

 

Shaneis: What type of light did you use to only affect the water plane? Is the plane the only object "included" for that particular light source? What is a general caustics setting to start with in the Vray Caustics dropdown? Thanks for your help.

[Devin Johnston]

I'm also having trouble with my caustics, I'm able to get them to show up but I can't seem to adjust their size. I've tried changing settings as well as moving the light with no luck.

[shaneis]

...What type of light did you use to only affect the water plane? Is the plane the only object "included" for that particular light source? What is a general caustics setting to start with in the Vray Caustics dropdown? Thanks for your help.

 

Well, I should point out that this is rendered in Maya using mental ray, so I can't give you any V-Ray specific advice. Sorry.

 

As for the light usage, it's a directional light (sun) and it is linked to all geometry in the scene. If you are setting up a caustics pass and you want to limit the amount of surfaces reacting with photons, you'll need to link the light with your water plane, the bath and the walls where you want your reflective caustics to appear. This will help for render speed, but for an accurate caustics pass, all the geometry should be present and included.