How to do a pool render with the camera in the water

[marc_gibeault]

Hi all,
I'm doing a pool cleaner, it's a commercial product not yet in production so I replaced it with some cylinders.

I'd like to give the impression of an underwater shot and have no idea how to do that.
Do I model a box enclosing the whole scene (with camera inside or not)? Do I put a plane with a disturbed water material so the light coming from the top is diffracted and produces some caustics?
Here is the scene (which needs to be optimized as it's rendering very slowly)
http://www.alto-design.com/images/ex...cleaner-01.max
(There is only one map used; the Campus probe to get some nice reflections.)
Thanks,
-Marc

[marc_gibeault]

I'm going out of the office untill tuesday... :P
Please don't be offended if I do not read your answers untill then.

Thanks,

-Marc

[DaForce]

You will certainly need caustics.
And maybe a fisheye lens will help give the feeling of being underwater.
Or perhaps a plane infront of the camera with a glass material and a ever so slight noise to the opbecjt or material so the view is somewhat distorted.

I will have a shot later today when I get home.

[jujubee]

Anoter thing underwater scenes tend to have are tiny particles floating around.

[marc_gibeault]

Thanks for the replies.
But I realized that this setup would not end with a convincing image of the product; I won't put it in contaminated water, it's a pool cleaner!
So I'll try to get a convincing image with the camera over the water. And I have these two problems:
-I don't get the caustics settings. The parameters of my VRay don't match the online help.
- I tried numerous water settings... I want the surface to be pretty smooth to have a good view of the product, but I'd like to have nice caustics on the pool floor.
The scene is pretty small with these simple objects, I made it available here:
POOL_VACUUM

Thanks!

-Marc[/url]

[DaForce]

Will have a look for ya

Have had some good luck with caustics recently

[DaForce]

do you want the camera above or below the water?

[Da_elf]

looks like he is looking for below

[DaForce]

ahh yes, but you need to look a little past that, in his second post he talks about the water being smooth so he can see the product and the max file he posted has the camera above the water.

[marc_gibeault]

Yep, the camera above the water.
Sorry for the delays between my posts.
Another project takes all my computing power

Thanks,
-Marc

[DaForce]

Ok above.. right... good to have that confirmed.

Will whip something up tonight.

[marc_gibeault]

I'm on the other side of the globe so this discussion will take some time

I was not successful with caustics. Some renders showed a pretty uniform patern of blotches and some showed... nothing.
And the water material is tricky too; a little bit of reflectivity to see the waves and the scene was all washed-out.
Maybe I was trying too many things at once but my results were surprisingly different. The caustics, the water, the environment, the light... Your help will be welcomed.
-Marc

[DaForce]

Hey sorry didnt get a chance to do it last night. But will definitly tonight.

When I looked at your scene the other day i think the problem was 2 fold... your distance was too great and you should just put 0.0 in density. Try lowering your distance a few decimal places and see what happens.

[marc_gibeault]

Hey sorry didnt get a chance to do it last night. But will definitly tonight.

When I looked at your scene the other day i think the problem was 2 fold... your distance was too great and you should just put 0.0 in density. Try lowering your distance a few decimal places and see what happens.

I tried again but I can't find what makes it so wrong... I have a bad time changing settings and just getting worse results
If someone could get me started...

-Marc

[DaForce]

Here is something to get you started. Its far from perfect... but it shows you that caustics work fine in your scene and how i chose to set them up. Which i recommend you stick with. Its basically a direct light specifically setup for casting the caustics, and no other lights add to the caustics solution.
Note, it renders out a bit dark, as a lowered the vraylight too much but you can fix that.

Anyway have a look.

DOWNLOAD HERE