What is GGro?

GGro is a Houdini toolkit designed to streamline the development of organic growth effects, from trees, corals and fungi, to any abstract system you can think of. It includes a few solvers and a lot of general utilities, which can also come in handy for other general tasks in Houdini.

How do you use it?

Each solver has its own quirks, but generally speaking they allow follow the same basic workflow:

• You start with a static mesh as an input
• You add a fuel attribute, which is “consumed” by the solver to grow the mesh
• You set a direction attribute, which tells the solver how to grow it
• You set a mask attribute, which can prevent certain areas from growing
• The solver calculates the displacement, remeshing, and a few other useful things
• You repeat for the next frame

All these operations are incapsulated in the solver, you don’t need to set them up by hand (although you can if you want to). At an abstract level, these operations translate to a network like this:

The actual details vary from solver to solver, and you’re free to take a look inside each of them if you’re curious!

Solver UI

The solvers UI is designed to be used from left to right, mirroring the internal flow of the solver.

The solvers expose all of the most important and most commonly used options, however you can dig inside and further customize the solver’s behavior using all of the GGro SOPs (and regular Houdini SOPs) inside the dive target.