I've been thinking about Mark's ocean rig and getting a more realistic wake for a boat traveling on it. I thought about displacement maps and sprite emitters. The sprite emitters would be easy to set up, but the displacement maps are another story.

Mark's rig is assembled in the chor out of one tile model, so how would one go about tracking a boat on a path in the chor with a displacement map? For that matter, is it even possible to do that on a basic grid? To simplify matters, is there a way to have a decal that is applied to the ground plane track and follow a seperate object? John?

What about an animated mesh to simulate the water build up around the hull? I'm thinking about a small mesh in the form of a basic bow wave with some displacement mapping and a couple of sprite emitters for good measure. The challenge would be to have the mesh constrained to the ocean rig and the boat while being animated.

I'm not smart enough to work these things out, nor do I know if it's even possible, but we have some really smart people here that might shed some light on this.

Please, everyone chime in, let's get the bow wave flowing...

Eric

I'm not sure you will be able to do it with displacement maps. Possibly with a material effector constrained to the boat, with the material set to displace.

At some point I want to get rid of the tile model and have it all in one model (right now it's 64 tiled models, in the ocean generator model, set as action objects in a pose). I don't have the time right now though, it's going to be alot of work. Just think, it's going to be 64 rigs in one model, that's why I went with action objects to tile the rig in the first place. Having it in one model will also get rid of the seams, allow the use of a spline for a path and surface constraint with separate path, across the whole model.

I was thinking about this the other day.. Why not use an animated displacement materiel with some type of turbulence on a long strip of patches (sine?) with a material effector on the front and back. The effectors would be a 100 percent transparency translucency deal. The wake would be non uniform and look more realistic. I was only thinking about this of course. I'll try it later.

AFAIK, material effectors don't work on a per object basis, they affect anything in their zone of influence. Getting one to act only on the water and not on the ship would be difficult.

Two cylindrical effectors in a V-shape, infront of the boat, may work. That was what I was thinking anyway.

Here's an example of a modeled wake. The water texture itself is only minimal but it demonstrates the concept.

Click to view attachment


The ball and wake never really move. The camera and water texture are moved past them to suggest movement.

Click to view attachment

Nice example Robert, but this will tough to do with the ocean rig. There would be a few problems. If done in the modeling window, all tiled models will have this. If done in the chor, the texture will be stretched, may not be too noticable. I guess your suggestion will require him to rebuild his scene.

No, it won't work on a tiled surface. But it is a wake.

I just did a quick test in the chor, this may work quite well, if the boat model is centered on one of the tiles.

Rendering test now.

I did this effect years ago with decals. You just have a decal large enough to cover the path the boat follows.
I think this could be adapted for current versions of A:M.
You can see the old tutorials here
Water Tutorials

Charles Babbage

A decal won't work here, Charles. The ocean is 64 models of the same grid, tiled in the chor.

Well, I guess you could set the percentage of the decal to 0% in the model, then in the chor you could set the one tiled model's decal to 100%.

this is gorgeous Robert.

I'm gonna try to model a separate small re-usable wake that can be used on any water surface.

The one key feature of a wake is that it's not just above the surface, it's also below. Its average is the regular surface level.

I would probably put a a displacemnt map(applied via material not decal) of the wake(similar to robcats wake shape, but a greyscale decal.) and animate its position on the surface of the water. More maps could be used for the foaming area behind the boat and sprites for the front where it cuts through the water.

However, I have no clue about this ocean rig, so maye it wouldnt work here?

Mike Fitz
www.3dartz.com

Mike:

Are you talking about applying a material to the ocean surface or a decal? A decal I can understand because you can draw one in the shape of a wake and animate it. A material in the form of a wake? Is that possible?

Mark:

How did your test render turn out?

Eric

I like the result that Charles got.

One problem with our new displacement is that with only 128 levels on each side of neutral, banding can become very obvious on nearly horizontal slopes. If you can fashion your map in EXR that will help.

Robert,

Did you create that wake model/ animation in A:M. Looks really cool.

Great tutorial!

Now...you know I wouldn't be cheating on A:M, doing cool things in some other app. It's all A:M.

This is very rough and not very practical, but I wanted to see what it would look like. The material on the wake needs a lot of help. I just made an fbm material (you can tell I don't know much about materials) and set it to displacement. The material needs to look much more like churning water when it is displaced (anyone ). It and the water are obviously translated over time. The boat is manually translated and then the wake is constrained to the boat with a bit of lag. Off course, with this you'll get no wake trailing the boat, but like I said, it's just an experiment. Get a better material for the wake, add some sprite splashes, and it wouldn't look half bad

edit: hang on, link needs fixing - done

Bow wake test

well, something that would help is ref footage:

http://www.youtube.com/watch?v=puPacN0rtRw

notice how the wake of a boat is more like the water being cut, and how it curls over itself before "exploding" if you will into tiny water particles.

I used a decal and decaled my wake with an image of a wake - used the same image for displacement (20x20 repeat) - 2000%, same image for setting transparency 20%, and ambiant intensity 75%, constrained the trailing wake to boat with lag (wake model(s) need refinement). I have 2 different shaped wakes in this sample, both decaled in same manner - just trying out different shapes and behavior. Here's the image I used for decal (I used only the wake part)