light rays passing through a water volume?

[arbolive]

Hi, there, im working on a water scene. but i dont know how to make a more realistic look (in pic 2) beacouse i need an under water effect, and some light rays passing through the water volume.

settings:

( im using LC + QM _ caustics are on_ and i'm lighting whith an hdr image, also color mapping is reinhard ( burn value 0.7) )

any advices?

if someone have any suggestion about theese images ( how to make them better, or what is bad ) i'll be very thankful

thanks.

[arbolive]

light rays passing through a water volume?

image 2

[arbolive]

Re: light rays passing through a water volume?

here is a good example of what im looking for:

see those light rays passing through the water. looks great!

thanx

[Travis Serio_cg]

Re: light rays passing through a water volume?

the last image seems like direct light would be needed and it would need to be volumetric at that. I am not sure that volumetric light is currently possible with vfr? Hope I get proved wrong on this one lol.

[dalomar_cg]

Re: light rays passing through a water volume?

Unfortunately, Travis, you are correct. Volume light is currently not supported in V-ray. That reference image is either a very good photo, or the result of quite a bit of photoshop (thats what it looks like to me at least). If your thinking that your renderings are going to come out like that without any post work, then you may need to change your expectations just a little bit.

That being said, the under-the-water render is very tricky because how refraction is handled by vray. Basically there needs to be an entrance surface and an exit surface (Micha and I had a little discussion about that here , that will give a little more of the specifics about the entrance/exit issue and how things can be handled) and right now the under water shot doesn't really have an entrance surface because you are in the refraction volume. What that boils down to is you have to model the water as a solid that has some void or something that the camera needs to sit in. Right now I'm not really sure if you have just that top surface and a few bubbles or an actual solid, but there needs to be some sort of entrance surface directly in front of the camera.

As for having the bubbles in the water, that is going to require that the water needs to be a mesh. The link to my discussion with Micha explains it in detail, but with nurbs v-ray can't read those bubbles as being voids in the main volume. If you make them meshes then you can control that.

[arbolive]

Re: light rays passing through a water volume?

thanks dalomar for that link; well , in my scane, my water is a solid, and yes , it was meshed, but i improved my bubbles, by changing the mesh normals ( as you said ) and, also changed the water volume mesh normals and the results are attached below.


with this change, the rendering process has turned very unstable (a few times the program showed me a pop-up window saying that the aplication has an error an it needs to be closed. )and slow , should be the heavy caustics usage, and reflections/refractions.

here is my image during the light cache calculations.

ah , so sad that v-ray dont supports volumetric lighting, does anybody knows if 3dmax version support's it?

thanks

[Micha_cg]

Re: light rays passing through a water volume?

Your scene show no diffuse surfaces that catch caustics, so you can disable it and save time and RAM.

[dalomar_cg]

Re: light rays passing through a water volume?

To me that looks a whole lot better...I think you might be crashing because your using up a lot of memory (allot of reflections/refractions will do that). When exactly does the render crash...during LC, during IR (if your using it), or during the actual render process? I'd suggest you lower the bucket size to something like 36X36 or even 24x24 (actually 32X32 is a more optimal bucket size because its a root of 2...2^5=32).

Volumetric Lighting is supported in vfMax, but its supported through max's volumetric lighting, not a v-ray specific one. Which means that Vlado would have to make a vray volumetric lighting thing for us to use.

[arbolive]

Re: light rays passing through a water volume?

jmm ok im gonna try what you said but i have a queston first, wich of theese controls is the bucket size option? ( im suspecting of one but i'd prefer to be sure). :-[


i've modified other controls based on those litle advices that shows up when i drag the mouse over the options, but those advices, dont show up in a few controls.

thanks

[dalomar_cg]

Re: light rays passing through a water volume?

Yes thats the bucket size

[Micha_cg]

Re: light rays passing through a water volume?

Do you use IOR 1.33? The water looks a little bit like glass.

[arbolive]

Re: light rays passing through a water volume?

i dont remember, cuz the first scene, had problems so i pasted the model in a new scene and the water material isn't appearing on the materal editor lay out. ( i remember i used that ior that you said in a test of a material in a previous scene but i dont know if i'd applied to it :-\. im gonna render a new one with that refraction index to check, thanks.

perhaps, here is a refraction idex list that should be useful for someone some time.


( the under water scene crashes it's maybe a memory problem. still trying )