Grid visible in Cap mode

[ben_hamburg]

Hi there,

I´m having trouble rendering a scene with a couple of fluid sims in it.
The idea would be to render one of the fluids in Ocean mode and all the others in Cap mode.
But one of the grids is clearly visible (I attached a render with an Override material for better visibility).

I moved all grids so that the ocean level should be on 0 on the Z-axis, so that shouldn´t be an issue.
I also tried playing around with the "fade out" value in the rendering tab, but that didn´t seem to do anything.

I also tried rendering the Cap mode fluids separately, so I could blend them manually, but from some perspektives the corresponding boat was visible below the surface, so that didn´t work out either.

Any ideas?

[Ivaylo Katev]

looks like the simulator is a bit above the water.
but eve if you put it below the water, you will have problems anyway. when the simulator produces a "hill", it will be visible above the water, but when produces "valley" it will be not.
the cap mode is made with the idea to make geometry with rectangular hole, to put the simulators in the holes and to use vray displacement for the geometry.

[ben_hamburg]

Hm, guess I never noticed that the simulators were capped by the ocean extension below the surface. I mostly used Phoenix to create boat trails and those "valleys" must have been hidden by the ocean displacement and the boat meshes...

Which worked fine for me so far when I had to put several sims in a scene.

the sim shouldn´t be above the water.
Its 3 m in the Z direction, pivot is at 0 and ocean level/initial fill up at 50.
The other sim that is set to render in ocean mode is 5m in z direction, pivot is at -1m and initial fillup/ ocean level at 20.

Actually:
The sim that has the ocean extension enabled had a Z size of exactly 5m at creation time, but now that I increased the resolution it shows 4.992m.
Could that account for the small difference that makes the other sims grid borders visible?

Apart from that: How would you go about rendering several simulators in the same scene?
What would happen if I enabled the infinite ocean on all simulators?

Right now I´m thinking of rendering the sim with the ocean extension in one pass, render all the other sims including the boats in a seperate pass and then just mask away the parts of the boats that become visible below the fluids.

Either that or just mask out the gap and do the old comp trick I did to mask the holes in the ocean extension toward the frames borders (that issue that got fixed in one of the nightlies).

[ben_hamburg]

I think I found a simple solution:

1. Render the main pass with the infinite ocean.
2. Link a Vray Matte Material box with alpha -1 to the other sims and place it right below the surface (accounting for displacement of course).
3. Render second pass with only the other sims / boats. That way I get a clean pass I can lay over the main pass and no boats poking out below the sim...

The borders around the simulator aren´t visbile if I do it that way.

[Ivaylo Katev]

sounds great, i will suggest this to other people, we already had such questions

[hstone2003]

I was just about to make a post about this. I need to have 2 simulators for the same ocean, 1 is a boat moving across the surface and the other is a character coming out the water. The scene was much easier to handle with 2 sim grids but didn't know how to get it to render as having both with the infinite ocean, they overlap.

At the moment using 1 grid for the whole animation its taking too long and I end up with a lot of wasted grid space I have to calculate.
Will give this a try and hope if works, thanks for that information

[ben_hamburg]

Just reporting back: Works like a charm so far.

There still is a little border visible sometimes, but since I have rendered with Cap mode I get a nice alpha channel to blend it better with the infinite ocean!

[hstone2003]

Any chance you'd be able to upload a demo scene to show how you got it to work?

[ben_hamburg]

Sorry, too busy right now. Just to let you know: It looked good first, but in the end I still had to do a lot of manual masking. The issue is not only with the boat visible below the water, but also the water mesh. I used the "clear inside" option, which actually forms a hull of water around the boat (where it is submerged). And that part just renders black. So the task here would be to find a way to color that part only, so you could at least key it out in post instead of manually masking the whole mess...