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In this tutorial, I am going to show you how to create tracks in the sand made by a tank or other vehicle.
Here is how it will work. We'll take a screen shot of the bottom of the tank and its treads. We will use this picture to import into Bryce to use as a terrain.
Because the terrain needs a grayscale map, we'll touch it up in Photoshop first.
We'll be creating a displacement map. A displacement map is different from a bump map. A bump map uses shadows to fool the viewer into seeing bumps in a surface. A displacement map actually conforms the surface so the surface is bumpy.
After applying the map to the terrain, we'll import our tank, and set up the scene, and I'll show you how to layout the new terrain so it will look like the tank created the tracks as it drove by.
It's a really nice effect.
The first thing we need is a tank. I'm using the free JAGDPanther from Vanishing Point.
I got it from Content Paradise.
You could use the M1 Abrams Main Battle Tank from DAZ too, but I'm going for all the freebies here.
The first thing we need is a render of the tanks treads, and the best way to get it is to turn it upside down and render it from the bottom.
Sometimes you can get what you need from the texture, but this tank has the treads modeled rather than just a drawn texture on a belt.
Open your copy of DAZ Studio and load the tank model.
Your screen may not look exactly like mine. I have my timeline on and docked at the top.
Now render it from the bottom like the picture shown. You may have to turn off the floor.
Make sure it is straight up and down. This will help in the next step.
Now save the render as Treads01.tif where you'll know where to find it later.
Menu: File | Save Last Render.
(I have included a zip file with this image in it).
I saved it as a TIF file because it gives me a much better resolution then JPG files.
Next open Photoshop or your favorite image editor and load in the Treads01.tif picture.
Draw a marquee around the middle parts of the tank so we can remove the under belly of the tank. All we want here are the treads.
Delete the entire picture in the marquee.
Desaturate the picture to get it to grayscale.
Why are we doing this?
Because if you use Bryce, or any other modeling program to do a displacement map, it requires a grayscale image, and desaturate creates a grayscale image from a colored photograph.
Invert the picture so the high points will be high and the low points will be low.
Why are we doing this?
Because of the way displacement maps work. White is high and black is low. Grey is in the middle. If we did not invert it then the treads would stick out of the ground. We want them to be depressed into the ground.
Set the brightness and contrast so there is just a bit of difference between the treads and the terrain.
I used -100 for the brightness and -70 for the Contrast.
Why are we doing this?
Because we only want a slight indentation. The closer the tread color gray is to the ground gray, the smaller the indention is. If you want really deep tread marks, then make the treads darker.
Save your new picture as Treads02.tif . This way if the brightness or contrast needs more setting, you can come back to it.
Open Bryce and create a new terrain.
Open the Terrain editor by pressing that little E next to the terrain, and click on the Pictures tab in the editing tools.
Click the Load button to load the Treads2.tif photo.
Press the Apply button to apply the map to the terrain. See how the treads depress into the sand? You can do this with any image, but make sure you have your colors set right.
Remember: White is the highest point and black is the lowest.
After you press the checkmark in the lower right of the screen, you will have a terrain object with the tank treads applied. Now we need to line it up.
But first we need a tank.
Press the blue S at the top to go into DAZ Studio again. We need to import the tank into Bryce.
I applied a sand texture to the terrain so I could see it better.
Load the tank and pose it as you like in DAZ Studio, then press the Bryce button to send it to Bryce. It's the button in the upper left of the screen.
It's huge! Yes, we will have to do a bit of scaling here. It does not matter if you scale the tank up or the terrain down as long as you'remember to scale everything else in your scene while you build it.
After you scale it then line up the terrain with the tank and you're done.
If you need longer tracks, then duplicate the terrain and move it behind the last, making a lot of terrains.
You could also have extended the picture in your paint program, and then created a larger terrain.
If you see the edges of the terrain and you want them underground, then go back into the terrain editor and carefully paint all around the edges of the terrain a darker gray. This will make the edges lower into the ground.
I may do a later tutorial showing you how to animate this process so it looks like your tank is rolling across the desert, but it's out of the scope of this tutorial.
Now add some trees and texture it.
The finished product!
Happy rendering from Gary_P.