I am having the worst luck generating caustics :(

[lehthanis]

Ok, so I got caustics to finally show up, don't ask how, because I don't know, they just started all of a sudden. But they are basically a bunch of round spots...big round spots like 6 pixels or so on a 640x480 render. And they're white and red...my material is red. I'm startin to get frustrated

[JeffPatton]

Ok, this may go down as one of the worst freakin' tutorials out there...but none the less here's the link:
My Mental Ray Caustic Tutorial (http://www.jeffpatton.net/MR-Caustics101.htm)

I just hope it doesn't confuse more than it helps.. :scream:

Jeff

Edit: I put the sample scene at the bottom of the page....I guess I should've put it up top so that people can work along with the tut.....'DOH

[nobrain]

like everything in mental ray world scale is important meaning ur units should equal real world. aside the blotches need to overlap to create an effect if they dont either ur radius (size of blotch) is not big enought to overlap another adjacent to it or u dont have enuff photons in scene increase freely to 200000 to 1000000, depending what u need.

[lehthanis]

Wow, excellent tutorial (except the text seems to overlap some of the images, but concept wise its very helpful...

I found out the reason my caustics weren't showing up is because my decay of 2.0 default was messing them up...I lowered it to 1.0 and it started working. I think my mesh density also has a lot to do with it...I'll tesselate or something and see how that works out.

I also probably really need to look at the world scale/size also...I'm pretty sure its currently set to basic max units. Here's my render so far...I'm assuming the d20 isn't making caustics because its shape channels them away or something? Looking at this though, can you see any obvious potential settings problems I should be looking at? I will probably increase the multiplier on my skylight...its currently got GI and FG on. There's a skylight and a mr area spot. skylight does NOT generate caustics (as far as I know)

Despite a few potential big problems, I'm still quite pleased with the results even though its not accurately done I guess caustics wise. Took 7:07 to render.

http://www.fantaseum.com/arcana/screenshots/polyhedrons/diceritual.jpg

[JeffPatton]

Wow, excellent tutorial (except the text seems to overlap some of the images, but concept wise its very helpful...

hmmm, what browser are you using? Just checked it again and the text seems ok in IE6. I'll have to see if there's something I need to change so it will look ok in all browsers.

[lehthanis]

hmmm, what browser are you using? Just checked it again and the text seems ok in IE6. I'll have to see if there's something I need to change so it will look ok in all browsers. I'm in firefox (only the greatest browser of all time) :D The tutorial was quite helpful actually.

Edit: Just re-rendered the above picture, this time with a .8 multiplier on the skylight and I used a subdivide modifier on all the dice to add density per your tutorial. I'm seeing hella caustics now. But are they too intense? what should I lower for that?

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