The documentation is being updated. There may be incomplete sections.
Create with Primitives
Most of Gaea's Primitives fall into this category. They generate basic geological shapes that can then be processed and eroded to look like a realistic terrain. Procedural generation allows you to create an infinite number of variations from the same node.
Primitives expose a property called Seed. Changing this property randomizes the shape. This allows you to create multiple primitives that follow the same general paradigm but are distinctly different shapes.
Primitives can be used by themselves, for example the Mountain node can help create a "hero mountain" without needing other primitives. Or multiple Primitives can be put together using the Combine node.
When multiple Primitives are combined, they can produce sophisticated shapes.
This video continues in Color Production.
Hand Drawn Primitives
The Mask node can also act as a Primitive even though it is categorized as a Data Map in the toolbox. However, it will not process the shape you draw.
To import a heightfield in any major 32, 16, or 8 bit image format, create a File node and load the desired file. You can simply drag and drop a valid file on the graph and a File node will be created for you.
Importing Meshes and Geospatial Data
Support for importing meshes as heightmaps, and satellite data such as DEM, SRTM, and other formats will be available soon.