Caustics - scale model

[sanny81]

Hey there,

i have scene with a pool and finaly i get it worked to render nice Caustic effects.
Now i need this Model bigger because i modelled it in wrong scale. When i scale my object
then my caustics dont work any more.
Tryed to increase some settings and now i desided to ask you in this forum.

What can i do?

[sanny81]

Re: Caustics - scale model

evry time the same issues with vray... i can not fix caustics... some times it wor -> sometimes not- and i dont have a clue why?
Why are there so much ways and settings to get only one effect ???
Isnt there a easy way? sometimes Vray is killing me...

[sanny81]

Re: Caustics - scale model

http://img227.imageshack.us/i/150pooleffects.png/

after scaling
http://img89.imageshack.us/i/shitp.png/

[arqestevez1]

Re: Caustics - scale model

that about the caustics is complicated... but i've learned one thing.
you may have your caustics settings ok, but you won't have caustics if your sun isn't at the right place...
you can also notice that you won't have caustics if you move your model to certain areas... for example, you may copy your pool several times in different directions, and you will see that caustics effect becomes more and more weak, untill it disappears...
so i would recomend you to consider this, and try to put your pool in the right position, so you can have the light effect produced by the sun...
and vray becomes easier when you understand it hehe

[fooprobe]

Re: Caustics - scale model

It's hard to tell from the pics, but if you're getting the water surface through mapping (e.g. displacement) make sure to increase the multiplier (edit: and texture mapping scale) there too. If it is geometry - it looks like it is with the fog color - then the caustics settings to play with are Max density (if it's non-zero) and Search Distance. These are both set in model units, so increase them by your scale factor. I don't think you'd need to change the max photons or multiplier.

very nice caustics! hope you can get it to work on the bigger one!

[Visa]

Re: Caustics - scale model

Have you tried decreasing the fog multiplier in your water material? More depth (scaling the model up) means more fog and if the depth gets too big, the light can't reach the bottom -> no caustics.

[sanny81]

Re: Caustics - scale model

Thank you guys for your help. I will try to in- and decrease the settings you told me!
And if i get it work i will tell you here how i get it fixed.

[sanny81]

Re: Caustics - scale model

Con not get it work... I have 2 Video Tutorials from Fernando Frentas and tryed it on both ways.
With Sun in Sky slot and with Omni Light... cant get it work.
If my Boss hear that i spend 10h for nothing he would kill me...
by the way i am not a noob anymore - i work with vray for rhino now 3 years but now i am feeling like noob... I am totaly angry of myself...
This caustic effects are killing me...


i use VfR 01.05.29

my settings:
modelscale is mm

Max Photons ca500
Multiplier 1 - 100
Max Density 0
Search distance 0.5 - 20

Light settings:
Photon subdivisions 50 - 5000
Caustic subdivision 4000 - 10000
Photon emitter distance 150 - 100000
--------------------------------------------------------------------
if i use Omnilight i get a Map i can save in Options
but cant get visible Effects from it...

and if i use Sun i dont get Map any more...
tryed several position... and angles...

[sanny81]

Re: Caustics - scale model

Get it work! But only with very high settings...



Uploaded with ImageShack.us

[Micha_cg]

Re: Caustics - scale model

So far I know it's important that the caustic photon rays of a sun light must be focused to a limited area. I havn't tested it, but the photon radius should be the right option, also look at photon distance (this option are wrong placed at the UI, should be part of sampling). This both option helps that the photons are not spread over an infinite area from an infinite distance.

For the omni light - it looks like the photons are spread in all directions. In your case not usefull, you need to much photons to see an effect.

[fooprobe]

Re: Caustics - scale model

ok, this is a little weird. i found that when using the sun the caustics get cut off on a line that follows the orientation (in plan) of the sun. i couldn't find what was causing the shadow, i had nothing in the model but the pool. so i tried moving the pool model in the z-axis, and that's what was doing it! here are four renders at four z-heights:



and here are the caustics settings i used (model units are inches):


so you may have to move your model down to find the caustics effects! ouch!