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Recipe for River Valleys by Jen de la Cruz

Jen's Recipe for River Valleys

This is for all of you Brycers out there who have tried to fit mountains together just right to make a nice valley. Or, it's for any of you who just plain like rivers... and hey, if you didn't like rivers, you wouldn't be here, right?

(Picture of end result of recipe, plus texture and clouds.)

Bryce 3D or higher
Adobe Photoshop (or another image program)

I used a Windows oven for this, but it should work in a Mac oven too. Extra detail on how to prepare ingredients is provided for beginners. Some experienced chefs could probably figure it all out from the pictures alone.

First, preheat Adobe Photoshop to 512 degrees Fahrenheit.

Fire up Photoshop and create a new file with dimensions appropriate for a Bryce terrain. I usually don't go below 512 x 512 pixels, since I think that gives me the nicest winding river. I could always scale it down later to 256 or 124, if I so desired. For these examples I'll show small halfsize versions of the results for each step. Like this! (ooh, aah, blank image. Big thrill eh?)

Next, use a black and white linear gradient.

Set your key colors (is that what they're called? I have no idea), to black and white. You know, the two at the bottom of the Tools window. It doesn't matter which is which.

Then, select the Gradient tool. That's the little white, gray and black rectangle beneath the T (text tool), if you've never used it before.
Doubleclicking on the gradient tool will call up the options dialog box. You want settings of... Normal, Opacity 100%, Gradient: Foreground to Background, Linear. Other settings will give you some interestingly strange valleys -- experiment!

Anyway, use the gradient tool to create a shading from black to white in your terrain image. Basically, you drag a line across the center of the picture horizontally, and that's the range of your gradient. A longer line will give you a wider gradient and a more winding river... a more narrow line will give you a straighter river. Here's two examples, the top has a wider gradient, the bottom one is more narrow:

Filter using Difference Clouds.

This is the fun part. Go to Filter (one of the choices at the top of the screen...), then go down to Render, then select Difference Clouds. BAM! Suddenly this looks a whole lot like a grayscale to height map, now doesn't it? Heh heh. That black, wavy line will be the river once you get this terrain into Bryce where it belongs.

If you don't like how your river turned out, just use Undo (Control-Z in Windows) to get your original gradient back. Or, reload, or re-drag the gradient, or whatever. Then redo the filter (Control-F is the hot key for this).

You get a different river every time you filter it! Ooooh, aaaah, neat ain't it.
I usually try it a few different times till I get a river I like. Here's the two gradients from above, filtered:

Save your chosen grayscale-to-height map as a .BMP (if you're using Windows. Mac uses, uhhh... a .TIF or something).

When in Bryce, do as the Brycers do.

Now, finally, leave Photoshop and go to Bryce!

Make a terrain. Now, edit the terrain. This should open the Terrain Editor (wow!). See that grayscale map of the existing mountain? We're going to replace it with your river valley. There's three tabs at the top of the screen: Elevation, Filtering, and Pictures. Go to Elevation (you might already be there).

Click Picture. It's one of the buttons on the left, for you newbies. Now go find your river grayscale and open it. Voila! There it is! You can now do whatever else you might like to the terrain. Erode it, paint in details, whatever. It might need some editing around the edges, particularly.
Click the checkmark to accept the changes to the terrain, and go look at your new creation. If you want a longer river, you could just stretch the terrain in that direction.

Here's a rendering of the scene so far, from a viewpoint I liked. The river area might not be too visible, except in the foreground. You'll really be able to see it later, when there's water, of course.

Just Add Water.

Of course you could just wing it from here, add a water plane and then move it to whatever level looks best. For you detail-oriented people, however, here's a more precise way of setting your ideal water level.

Select the valley terrain and go back into the terrain editor. Use the clipping bracket (waaay on the right side of the screen. Looks like a bracket. Neat, huh?), and pull it up at the bottom bit by bit. Gradually you'll see your intended river fill with color to indicate the area being clipped. Tweak this until your river's about the width you want it to be, then hit the checkmark to accept the changes.

Now, back in Bryce proper, what you want to do is go to a side view of your valley terrain. Don't use the trackball to do this -- select the new viewpoint, using the view selection doohickey (just under the nano preview window). Zoom in so you get a nice close-up of the terrain. Can you see the flat, clipped bottom-edge of the terrain? If not... maybe it's underground or something. Turn Underground off, or just drag the valley terrain up a bit so you can see.

If you rendered the side view right now, it'll look something like this (depending on which side view you picked):

NOW, finally, create the water plane. It'll pop into being, probably rather higher than you want it to be. Use the Edit controls (or the Attributes dialog box) to move it on down so it's at the SAME level as your clipped bottom edge of the terrain. This will make the river fill the exact area you indicated through the terrain clipping.

Now if you rendered it in side view, it'll look vaguely like this:

Okay, now. Select your terrain again, edit it. Once again you see the valley from above with the clipped area marked by color. Drag the clipping bracket back to the original location, so that the terrain is no longer clipped at all. This way you still have the riverbed beneath the water surface. Click the checkmark and get out of side view so you can see the valley more normally again.

Here's a test render from the same viewpoint used before, but now there's water. Doesn't look too bad, does it?

That's all, folks! Now add texture to your terrain and weather and so on and so on.
You know how to do all THAT stuff.... riiight?

Of course I chose a more aerial viewpoint so you can better see the river, but I could have gone on down and taken some eye level pictures too. It all depends what you're looking for, really.

Add Texture to taste. Serve and enjoy!

So, here's my final render of this example with textures and clouds.