1. Starting up DarkTree 2.0.
When you start DarkTree, the first thing that will come up is DarkTree’s main window. This is split into two sections: the Texture Library and the Bitmap Renderer. The right side is the Bitmap Renderer where you can render out procedurals to bitmap files.
The left side of the main window is the Texture Library. This is a place where you can browse existing procedural materials and shaders. The bottom half consists of a filtered Explorer like file viewer. When you select a material in the list, you will get a description and rendering of it on the upper half of the texture library. If you want to see how the material is built or examine it at a larger scale, click on the Edit or Examine buttons.
2. Creating a new material.
To create a new material, select the File>New menu item on DarkTree’s main window. This will bring up a darktree editor (note: the procedural materials made by DarkTree are called darktrees).
On the left side of the DarkTree Editor, you will find a series of folders containing components. Components are the procedural building blocks that are used to make darktree shaders and textures.
To add components to a texture tree, simply drag the component from the list and drop it on a socket. When you drop the component, you will be asked if you want it to be color, percent (greyscale), or bump. Generally, you will use color to specify the color of your texture, percent to control texture attributes, and bump to specify the bumpiness of your texture.
There is one special socket called the Root Socket. This socket is where the result (or root component) of a texture tree is located. The component that is in the Root Socket shows what the current darktree looks like.
3. Starting a Rock surface
Now we are going to start making a texture. For this tutorial, we will be making a rocky texture that would be good for ground cover.
Lets start by dragging out three components: Add, Gravel, and Pumice. We will use these three components to make a bumpy surface for the rock.
First, drag out Add from the process folder and place it to the right of the Root Socket. Select bump as the type when you drop it. Next, drag a bump Gravel component from the Natural folder and place it to the right of Add. Finally, drag a bump Pumice component from the Natural folder and place it below the gravel component.
Make sure the three components you dragged out were pasted as bumps. You can tell by the blue disk on the left side of each component. Color components have a green disk, percent components have a grey disk, and shaders have a purple disk. If you made a mistake, you can right click on the center of the component and select “Convert Subtree to Bump”.
4. Linking up the bump subtree.
Now we need to link together the three bump components that you dragged out in step 3. What we are doing is adding the rough pock marked look of Pumice on top of the rocky look of Gravel.
First, link Add’s Bump A to Gravel. To do this, right click on the right side of the Add component. This will pop up a menu of all the parameters that Add can link to other components. Select Bump A. Once you do this, you will have a blue line attached to your cursor. Move the cursor over the Gravel component and click the left mouse button. The preview in Add automatically updates. Your results should look like the screen shot to the right.
Now link Bump B to Pumice. Once Pumice and Add are linked, you will see how Gravel and Pumice look added together.
Note: If you ever need to unlink a component, simply left click on the link and drag it away from the component.
5. Editing Gravel’s Bump Scale
When Gravel and Pumice are added together, the roughness of the Pumice hides the more subtle bump of the Gravel. For this tutorial’s rock texture, Gravel’s bump should be more pronounced and so in this step we will edit Gravel to make its Bump Scale higher.
To edit Gravel, double click on its component (you can also right click in the center of the component and select “Edit Component”). This will bring up the component editor where you can adjust parameters and transforms (translate, rotate, and scale).
Now, set the Bump Scale (lower left corner) from 0.250 to 0.600. When the value is changed, the preview will automatically update showing a deeper stronger bump texture. Press the OK button and look at the results in the Add preview. The bump part of this texture is now finished.
Note: If you want to learn what the various component parameters do, there is always a Help link in the component editor directly below the Ok/Cancel buttons.
6. Adding some color.
Now that the bump part of this rock texture is done, let’s work on adding some color. Here, we are going to use Pumice for the basic rock color.
First drag out a Pumice component from the Natural folder and place it in the socket right below the bump pumice you have already worked with. Choose Color when it asks you what type to Paste As. For this texture we want slightly milder colors than the Pumice’s defaults so double click on the color Pumice component to edit its colors. Set the Pit color to something like R=100, G=197, and B=70.
Now lets examine the bump and color parts of the texture to see how they look together so far. First, right click on the middle of the color Pumice component and select Examine. You will then get a popup window with the choices: Surface Color or Environment. Since we are using this texture for the surface color select Surface Color. An examine window showing the color pumice will now pop up.
Now drag the bump Add texture and drop it on the Examine window we just opened. (Note that you must drag from the image area of the component. If you drag the frame, you will move the component instead.) Another popup window will appear asking you what attribute to use the bump on. Select Surface Bump. The examine window should look like the example.
You can continue to drag textures to the examine window while you work to see a large view of your results.
7. Linking in a little lichen.
Now that we have a basic rock color, lets add some flecks of green to add lichen. Start by dragging out a Rough component from the Noise folder and placing it to the left of the color Pumice. Paste Rough as a Color. If you need to move Pumice over to make space, drag it from its frame.
Now lets edit Rough to make it generate little green flecks. Double click on Rough to bring up its component editor and set the High color to something like R=63, G=127, and B=63. Next, click on the Scale button and scale down the texture by setting the X field to 25.0 (meaning 25 percent of its current size). You will see the preview scale down immediately. Next, set the Brightness to 10% and the Contrast to 75%. This will result in sharp green patches that we will use for the lichen. Press the OK button to close the component editor.
To blend the lichen with the rock color, link Rough’s Low parameter to the color Pumice component.
8. Darken the gaps.
Our next step is to add some extra realism to the texture by darkening the nooks and crannies of the rock surface. This will give you a look like the higher parts of the surface have been more weathered than the deeper parts.
First, we will need an extra socket space to place the darken component. To do this, move the Rough/Pumice subtree one socket to the right. To move a component, left click on the right side of the component frame and drag the component to a new slot. You can move one component at a time or shift drag the leftmost component to move the whole subtree.
Now, drag out a Darken component from the Process folder and paste it as a Color to the left of Rough. Then drag out a Gravel component from the Natural folder and paste it as Percent directly below Rough. Now link Darken’s Background to Rough and link Darken’s Mask to the Percent Gravel.
You should now be able to see the texture darkened based on how dark the Gravel component is. For this texture, we would like the darkening to be a little more subtle. To reduce the amount of darkening, double click on Gravel and increase the Background value to 30%. This way, the darkening cannot be any darker than 30% of the original color.
9. Tie it together with the shader.
The final step is to combine the bump and color together using a shader. This will give you a fully shaded material that you can render out as a bitmap or bring into any of the Simbiont plugins.
First, drag out a DarkTree Shader from the Shader folder and place it in the Root socket. The root socket is the left most socket and is labeled Root.
Now link the DarkTree Shader’s Surface Color to the Color Darken and the Surface Bump to the Bump Add. Your entire texture tree should look like the example to the right.
If you examine the material, you will notice the surface is a little shiny. That isn’t really appropriate for this kind of rock so double click on the DarkTree Shader component and change the Specular Level to 0% and click the OK button.
You are now done building a procedural material in DarkTree 2. If you are running in demo mode, you won’t be able to save the results. If you have a registered version, you can now save the procedural material by going to the File menu and clicking Save or Save As and then choosing a file name.
Note: A second introductory tutorial is available here that shows you how to add tweak controls to this rock texture.
Copyright © 2006 Darkling Simulations, LLC. All rights reserved. Any questions? Mail me! email@example.com