hi… caustics problem… is there any way to differentiate between reflected and refracted caustics in vray? it would be great if there were seperate multipliers for each, but since there arent, what material properties control the strength of the two types?
i have a swimming pool, with vray lights set into the side of the pool.
the caustics reflected from the underside of the water surface onto the sides of the pool look great, but very little light escapes through the surface and up the walls around the pool… to get the caustics outside the pool bright enough, i have to completely bleach out those below the surface.
i have the water surface set to not cast shadows, it is a standard material with vray maps since it gives me more control over the opacity settings.
i tried a vray mat, but i have the same problem…
i have a fresnel falloff on the opacity since it makes the ripples in the water look lovely, but adjusting the opacity doesnt seem to help anyway.
ill post an image if necessary but i guess the problem is pretty self explanatory…
colour mapping? that will colour correct the whole image! surely there must be a way to control reflected and refracted caustics independantly of each other??
this is gonna be part of a huge scene, and i dont want to have to set up the whole scene so that i can colour correct it just for one bit of caustics…
show me an image of how far you got. And color mapping is a little different then color correction. You can do things with color mapping, with color correction never. Its basicly a dark and light multiplier.
You could benefit from it quite much…
here it is… its a very rough test, just to get materials and lighting… it will be used in a big project, landscaped beach club with thousands of plants, people, buildings… (people diving into the water etc.)
as u can see the caustics practically stop at the surface (there are some getting through but not a lot…) i appreciate that i can boost them up using the colour mapping, ( basically colour correction on vray’s internal 64 bit image as far as i know) but surely this means that anything else in the image with the same brightness range will be boosted by the same amount?
id LOVE to be proved wrong, cozs it would sort out my problems… buty what im really after is: which material properties determine the strength of the reflected caustics and which control strength of the refracted ones?
you surely must be able to adjust them relative to each other rather than just brightening up the darker ones?
anyway, thanks for your help losbellos, youre the only one to attempt it, and i was rude to u :roll:
Just a thought - is the water a surface with no thickness or is it a solid filling the pool? The reason I ask is that I had a similar problem with some curtains. I modelled them by extruding an open spline. They wouldn’t let light through until I gave them a thickness.
I think giving it a thicknes would work better, that or making the water a volume which fills the pool as real water would. If you choose the ‘fill the pool’ option I would make the water bigger than the pool so that the sides of the water and the sides of the pool are not coincidental. See all the posts re. wine glasses filled with liquid.
in my case even without (sorry I missed this) color mapping does work well. If u use lights below the water surface It that makes troube, you wont see the caustics. Lower maybe the multiplier. By the way your image looks cool to me. Here is my try.(without thinking too much on design
losbellos: thats a good point :? but i have a hunch my client would be dead impressed (sparkly things tend to impress them ive found :roll: )
j-bug: yes i started using vray lights, on default attenuation, but i found by switching to spotlights with inverse fallof, i had much more control, and seemed to need less photons to create a nice effect (like quarter as many :?: )
im not at my workstation now…back on mon. do some more tests then… ta guys.
Good boy, then listen and dont oppose please the solution is very simple (we target the effect) you put a spherical VrayLight above the water surface. Exclude all other objects (except water surface) from shadow casting and illum. Make the multiplier something around 5, then set how many photons should it shoot, and the caus multiplier for this light should start around 30.
This vraylight will make a bautifull caustics underwater and on the walls. Both. Balanced look. Tweak.
After you satisfied with the result you could put some photometric free point lights bellow the water surface just to light it up a little bellow. Whatever. but dont put too strong light otherwise it kills the caustics bellow.
If the light isnt enough outside put some fillight.
This works I tried out. If you have trouble I’ll send you the scene for study
An andvise you better use mesh not a bump mapped fake water. Less trouble with it…
that isnt a bump..its a reactor water surface… i have it set up so i can have people dive in and affect the surface… combined with some particle spray it should look pretty good… animates quite nicely..just need to up the faces for the final anim.
ill post a test anim when ive had a mo on it, doin another job while i wait for info on this one…
nice idea bout the vraylight … it does seem like the best way to do it :lol: although id still like to know how to vary reflected and refracted caustic levels independently..
well in fr-stage 1 at least u can differentiate between the two.. you dont have a multiplier, but at least you can switch them on and off independantly (in fact you can do this in vray for gi-generated caustics, but not for direct light ones…) that much control at least would be nice.
i fail to see why it would be a useless feature to be able to adjust two, essentially seperate effects, err, seperately. the fact that ive come to a point where im having to look at work arounds involving excluded lights and colour mapping to get the effect i want suggests that it would be a nice button to have. i know for a fact im not the first person to ask about this so its not just me being super picky.. (flipside..i believe this is a feature u quite liked the sound of..?)
to be honest i wasnt expecting someone to say “oh theres some multiplier settings hidden under such-and-such tab”
more like
" the material properties that affect how strongly caustics are reflected are this and that, and the refractive ones depend on such and such"
the differentiation is not covered in the manual..
