SHIP WAKES IN VUE

Ships and boats, at sea or on rivers and lakes, always have a wake when moving. But how to re-create that in Vue?

The basic trick is that you can drive a material function, with a "Distance to Object Below" node, in Vue6 or 7, or in Vue 7 use the "meta waters" which already have that function ;)
It's the same thing as for making water for shorelines. I won't go into how you make the foam material appear at a certain height in this tutorial, sorry (you can find such on the Net and I may do one myself some time).
I'm just going to show you how you can use such a foamy water material to make a wake under a ship.

The way this works is that, since all such functions require an object underneath to create the foam to appear, you can use a terrain shaped like the ship's wake, placed under the water, it will trigger the foam to appear!
You don't want the terrain to be visible at all, so you set it to be "Hide From Render", so it won't show up in the final render at all ;)

Also, use the CLIPPING brackets, to cut out the surrounding square shape you do not need that! Only need the "ship wake" shaped centre part.

Not bad, eh? :) Not perfect though, the edges are too hard, and it isn't perfectly shaped all around the ship. Some post work in 2D would make it better though.

But, there's a way to get the terrain shaped much more accurately ;)

The plan is to render the underside of the ship, this will leave you with an image of just the area of the hull below water. This will give you a perfect guide to base your wake terrain upon!

• Ok, what to do is, either temporarily convert your water plane to the flat black material you'll find in the BASIC material folder that comes with vue, or load a ground plane and position it at the same height as your water and convert it to the flat black material. This is so you have a background for the render.
• Me, personally, I'm always careful about such changes and would make a seperate copy of the scene file first, before doing such major changes...sucks to screw up your only file by saving it with the wrong material...Not that I'd ever do anything like that and scream and shout about it, ahum! ;)
• Next, put your camera directly below the ship. You may need to move your ground plane down to get enough space for the camera. Also make sure the camera is vertical, go to the tab in top right hand corner where you'll find position and rotation for objects (Numerics tab), make the camera Pitch 0 Roll 0 Yaw 270, so it points perfectly straight up.
• Make the ship a white material, so it stands out well.
• Add a Directional light, move it so it points up at the bottom of the ship, to light it.
• Render the image but make sure the render output is a SQUARE format, like oh, 1200x1200, or whatever size you want. This is because terrains are square. You will apply this image to the terrain, if it's not square, it will deform! You're trying for a decent fit around the ship. Save as bmp jpg or whatever you wish, suitable for editing in your 2D art package.

Now, the image is a bit dark, but doesn't matter, it's a guide for painting in your favourite 2D image editor, like Paint Shop Pro, or Photoshop etc. You want to imagine creating a heightfield, to push up a terrain, to look like a ship's wake. Think how a ship's wake looks...high and a bit broad up near the bows as it slices through the water...tight around the middle, and long and fading away from the stern.

So, paint away in a greyscale, white = super high, remember, and mid grey = water level! Vue though is a bit barmy, and usually it INVERTS greyscales compared to every other app I know...grrr..so be aware you may need to hit the invert button in Vue ;)

If you wish to be ultra detailed you can make the painting in 16 bit mode, but it's not vital unless you wish to actually sculpt a really sweet physical bow wave (see below). Just a nice approximation will do, thus 8 bit image depth is ok.

IMPORTANT NOTE! you must, must have the edges fading to black. Wakes aren't solid "foam with a dead obviously fake CGI edge!", nah, they are turbulent fading into the surrounding water. So, a straight hard edge would show up fake. So I draw my image, then gaussian blur it to provide a soft edge. You can use many tricks/styles of painting and layers if you wish to. Usually though, the foam material will add nice randomness.

Another note: if this is for say a small boat, like a row boat, obviously you don't want the terrain water to show INSIDE the boat, lol! ;) So, make most of the inner area black, you can always carve it out in the Vue terrain editor, to tweak it by eye for precision if need, comparing to the boat's renders.

INITIAL PAINTING, I used some texture filters to roughen it up.

Ok, now you apply that image to a terrian in Vue, with your water material. You will probably still need to scale and squash it a bit to fit your ship, but it should fit much nicer, now.

Also, you will probably need to scale the height of the terrain object itself, in Vue, to be quite tall, oh maybe 3 or 4 metres tall or so (depends totally on the scene), this makes the edges of the terrain tumble down...which makes the "Distance to Object Below" function create a smooth edge gradient, not a hard, fake one. Very import to note this.

You will have to tweak and test to get it nice for yourself. You can have a duplicate of the terrain poking a bit above the water, to form a bow wave, just give it the same material as the surrounding water, edit the edges height and breadth to suit (don't make it so high, as you won't need the tumble) maybe tweak to add more foam. (and you can sculpt that more, or even add an extra terrain or rocks with the water material for dramatic realism)

In post work, you can use Smudge and Liquify or Warp tools to blend the wake in better, and sculpt waves too. Which is what I di din the "Lost River" pic.

Also, remember that sailing ships or slow vessels, do not churn up as much wake as high performance speed boats! ;)

I hope you find this of use! :)

All original art, writing on this site, copyright of Steven James, "Silverblade the Enchanter" ©2010