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Draw to Modify

A hidden gem in Gaea is the Mask node. On the surface it appears to be a simple mask drawing tool, but when used in conjunction with specific node networks, it can give you a powerful creative advantage.

In this example, we will use the Mask node to modify the heights and even draw some detail into an existing terrain.

To set up our Mask node, we input the terrain for reference so we can see where are drawing. Then a Combine node is set up after it to take the Mask output and blend it into the main terrain in either Add or Screen mode. Finally, we Pin the Combine node so we get a live preview of the result from the drawing. (see Pinning Nodes).

In the Mask node editor, click Edit Mask to start drawing. Adjust the Blur and Iterations until you get the right level of softness. More softness means gentler transitions for the main terrain. Remember to use a low Strength setting in the mask editor.

If you need both raise and lower capability, you can set up two different masks - one that Subtracts while the other Adds. Or you can choose 50% Strength and paint over the entire mask surface. Switch the Combine node's mode to Multiply and in the Post Process Stack set the Multiply option to 2.0 to compensate for the 50% multiplication. Then when you use positive or negative strokes, they will raise or lower respectively.

For added shape randomness, you can use Warp before combining the mask.