Displacement for ocean

[craiggorton]

I want to use displacement for my ocean. First some background:

Before the infinite plane and before displacement came around, I used to make a huge disc (216,000 inches radius) to simulate the ocean. I used a bump map and it was only a hassle because zooming extents would zoom way out.

Then infinite plane came along, and now I'm happier. But displacement looks even better than a bumpmap. The question is, how to use displacement on an infinite plane? It doesn't seem to work, even if I adjust things in the material's mapping. There's nothing there at all.

Okay, so if that doesn't work, I can go back to my huge disk and apply displacement to that. So I'm trying that now and getting some crashes. Before I do too much testing, does anyone have advice? (I've read the manual.)

Should I apply custom render mesh to the huge surface? Does it matter? Should I cut down global displacement subdivs, etc.?

I'd prefer not to cut-out a small area around the boat for the displacement because a) I'm lazy, and b) the reflection of the sky is different using a bump map vs. displacement.

I'd like some gentle waves, like 6" tall. And I will bump a bump map on top for the ripples.

Ideas, textures, comments welcome.

Thanks,
Craig

[Calderon]

Re: Displacement for ocean

Hi! unfortunaly I'm not going to tell you how to use displacemente on an infinitive plane because I don't know how, I don't even know how to use displacement on a common objet so this reply is just to know if you could explain that to me please, how do i aply displacemente?

Thank you very much

[Micha_cg]

Re: Displacement for ocean

I would test displacement at a finite ground plane first, maybe you find out, that the render times are too long. If you test it, please let it me know.

[dalomar_cg]

Re: Displacement for ocean

As I'm sure you've found out by now displacement doesn't work on the infinite plane (I can't remember whether its a thing with us or just how the infinite plane is, but my guess is the latter). So here's my work around...if you put your huge disc on its own layer (in my example the layer name is groundplane) you can then hide or unhide that layer when you want it/don't want it. If you're super lazy (like I can be from time to time), then you can put that whole action into a button to automatically hide/unhide it for you right when you render...here's the macro

-_layer on groundplane enter
_render
-_layer off groundplane enter

if you name your layer as something with a space then you'll have to put quotes around the layer name.

Hope this helps out

[Micha_cg]

Re: Displacement for ocean

I mark my hidden layers with "°" and use the this button script, that turn on all ° marked layers for rendering. So for example large ground planes are visible for rendering only.

! _setredrawoff
_-Layer _On "*°*" _Enter
_Render
_-Layer _Off "*°*" _Enter
_setredrawon

This button is part of my render tool collection.

[ALTO]

Re: Displacement for ocean

I want to use displacement for my ocean. First some background:

Before the infinite plane and before displacement came around, I used to make a huge disc (216,000 inches radius) to simulate the ocean. I used a bump map and it was only a hassle because zooming extents would zoom way out.

Then infinite plane came along, and now I'm happier. But displacement looks even better than a bumpmap. The question is, how to use displacement on an infinite plane? It doesn't seem to work, even if I adjust things in the material's mapping. There's nothing there at all.

Okay, so if that doesn't work, I can go back to my huge disk and apply displacement to that. So I'm trying that now and getting some crashes. Before I do too much testing, does anyone have advice? (I've read the manual.)

Should I apply custom render mesh to the huge surface? Does it matter? Should I cut down global displacement subdivs, etc.?

I'd prefer not to cut-out a small area around the boat for the displacement because a) I'm lazy, and b) the reflection of the sky is different using a bump map vs. displacement.

I'd like some gentle waves, like 6" tall. And I will bump a bump map on top for the ripples.

Ideas, textures, comments welcome.

Thanks,
Craig

Same problem with ocean displacement, strange thing is that first view rendered at 1000x750 px took 45min... at double resolution 6 hours!!! is this normal?
Second view at 1000x750 1h10min at 2000x1500 Rhino crash with no reason (memory usage was about 1.8 GB), Any hints?

Thanks

[Micha_cg]

Re: Displacement for ocean

I suppose so, Damien could know more. But I have a question too - doe's displacement works on infinite ground planes? Last I tested it, but I got no effect. Should it work and if yes, is it recommended to use it or is the memory usage to high?

[dalomar_cg]

Re: Displacement for ocean

Displacement does not work with the infinite plane. The infinite groundplane is dynamic geometry, meaning that it is not an actual piece of geometry that gets exported with the scene mesh (no faces, just the orientation/location of the plane itself) and that it has to be created at runtime. Displacement is also dynamic geometry. The main thing that displacement needs is faces in order to subdivide and create the effect. There are no faces within the infinite geometry, so there's no way to subdivide it.

My suggestion is to create 2 ground planes. The first is a smaller piece of geometry centered around whatever is deemed important enough to receive the displacement effect. So this would be around the boat and in the area from the camera to the boat. You're also going to want to have an infinite plane and have it so that is just far enough underneath the piece of real geometry so that it doesn't show through the displacement. On the infinite plane you'll have the same material, but just with a bump map instead of displacement. As long as you manage the edge where the real geometry stops (ie have it far enough in the background, a DOF effect or something) then you shouldn't notice a difference.

ALTO,
As far as you're scene taking that significant of a longer time with the increase in resolution, remember that one of the key settings for displacement is the edge length that is set in pixels. So if you double you're resolution and don't double that value then you are going to have to create significantly more faces then you were at the lower resolution. This takes longer to compute, more memory, and overly detailed geometry which makes raytracing longer. Increase that setting and that will hopefully bring the time down.

[ALTO]

Re: Displacement for ocean

Thanks Damien, yes i've changed the Edge length but i think is not enough :'(, i will try to increase more that value and maybe reduce also the Max subds...