Caustics achieved in Blender

After some playing around with this concept, I think I have finally achieved a way to simulate caustics with an internal Blender render. There is no post production on this Image and no external ray tracers were used, this is an internal Blender render. Feedback would be much apprectiated.

it seems as if you just used a small colored spot, it would be ok for low res pics of spheres, but it doesn’t look right for the blocks.

Well, the causic effect ‘might’ be ok… but the objects you used don’t look transparent at all… well, they are slightly transparent, but not enough, and they seem to have exactly the same level of refraction as the air, so even in the real world, such objects won’t create caustics I think.
The shadows are too “solid” too. It looks like you used the z-transparency for this image, you could have had much better results with ray-trans, and small colored lamps to fake caustics.

What is caustic effect?


Caustic effect is basically the reflection of the colored light that bounces off of or goes through an object. If you hold a transparent or metalic object above a surface while it is in the light, it leaves a colored or white light.
Anyway, I did actually use ray trasparency, but I cant get it to look really transparent, and I’m honestly not sure what you ment by “as transparent as the air” Solid shadows are a result of the area light above them (maybe not the best choice now that I think about it) I’m doing a new render with some floor texture and new lighting to see if that helps. I’ll post that soon.

It’s not “as transparent as the air” but with the same index of refraction as the air :wink:
What I mean is that the floor than can be seen through the red cube, for example, isn’t distorted at all. That’s why it looked a little like z-transparency. Try to increase the IOR value on your material settings, I think it’ll look better :slight_smile:

I agree with Rore. This is especially important from a realism standpoint, since an object that has the same Index of Refraction as air will not create caustics. It is the boundary line between materials with two sepearte IOR’s that causes ray bending responsible for caustics.


Lol. :smiley:

Sorry have to agree, this doesn’t look like caustics, just looks like you shoved a coloured lamp next to each object where the caustic would probably be.

Might as well just use yafray if you really need caustics in a scene. :stuck_out_tongue:

maybe he just put a lamp where he thought caustics would be.cause look at the green one.shouldent the caustics be in the shadow or on the oposite side.




(PS, edited the title for you)

:o whoa, oook, ya, wasent really yelling (oh and by the way, the post exile emphasised his too) Anyway, I give up on this stupid caustics effect, it was just a test to see if I could do it. I kinda added to the “bad posts” (which seem to be adding up around here) anyway, sorry I emphasised %| but ya, I’m through with this post.


A caustic’s grainier, not that smooth and pronounced. It also tends to be not a perfect circle. Try again. Or just use the filter settings.

It’s a little bit late but anyways…

You make it sound like it was radiosity. I read from that caustics were the ray of lights bouncing off reflective surfaces and/or being refracted by material (with IOR different from the air’s). These rays of light would not end in the camera, otherwise, it could and would be done with raytracing.

Is the last paragraph correct? I guess I should start a new post, but it’s late and I’m tired (good excuse…) So, can caustics be achieved without post-production? Can it be achieved without plugins? Can it be done using solely blender internal renderer?

Sorry for the harsh questions, I do not mean to be rude.

As to the image, it is true that the absence of IOR make the objects look as if they were made out of “camera colour filters”. You know, the kind of filter you see on cameras or clubs’ lights. They do not deform the rays of light.

What’s the point of making bad caustics in Blender what you can get excellent caustics using Yafray.

You do know that it’s free right?