I started playing Planetary annihilation: Titans because some friends said it was the best RTS for solar system domination. So I picked the game up and I began to edit some maps that other people posted that weren't quite finished products. Then I said you know what i will make a planet from scratch and see how that goes. The terrain editor is way to simplified, and not to mention the simple fact you can only mesh plateau with plateau so often until the map becomes a series of blended meshes that make for an unfavorable landscape design. I was sitting here thinking of easy implementations of terrain editors that would be overwhelmingly easy to get use to. Then I remembered playing this game "From Dust" that had a simple click to raise click to lower terrain method. Would something like that be even possible to do for a mod? Am I just the only one trying to even fathom a new terrain editor tool.
Nothing in the game hints at the engine having that capability. The most that can be done is low level editing of planet types (which are a pain to use) by extremely indirect noise functions, and I don't believe the heightmap is even controllable by that method.
Sadly, it's not in the engine at all. Respectively it is in, but it's not exposed at all. We would have needed the option to provide a user defined function for height/terrain maps as a substitute for the 3D Perlin noise currently used. That's actually much easier than it sounds at first. There is a clean interface internally in the engine which would be perfectly suited for this task. You could even hook up any arbitrary terrain generator of your choice if it was exposed. The only requirement for the generator function is determinism. Every client must be able to generate the very same planet from the same seed. The seed itself CAN be more complex than just a simple number. In fact, the alternative noise functions used to generate e.g. metal planets are already a perfect example of how you would interface.