01 Setup
Get Natsura installed and Houdini open before you start, so the rest of the series has somewhere to grow.
02 Navigation
Find your bearings in Houdini and on the Natsura toolbar. The fundamental tools, left to right, are Simulate, Grow, Split, Switch, Mapping, Effectors, and Decorate, with the Assembly and Scans workflows alongside them.
03 First Trunk
Drop a Simulate, the engine that grows the plant, add a Grow, and set its max growth steps to about ten for a single trunk. Start Width Scale and Width Scale per step do most of the shaping.
04 Decorations
Meshing is handled by decorations: standalone meshing processes you assign to a Grow rather than building a graph downstream. Remove the placeholder Trunk Preview, assign a Surface Decoration, and give the tree its material with a Surface Resource.
05 Assemblies
Branches and clusters come from the assembly framework: prefabricated, rigged models you assign to the tree. Pick parts on the trait graph by angle and size, assign the decoration to the Grows, and map the selection by height.
06 Effectors
Effectors are how you build your own controls for shaping the tree. The shipped library is ancestor, deflection, gravity, magnet, noise, and direction. Add a Gravity Effector to the Grow, flip its direction, and map its strength by u for an arcing shape.
07 Shaping
Shape deliberately by building a whole mapping graph rather than a single Map. Combining Maps and blend modes lets you control each branch locally and vary the shape by where you are on the trunk, then flatten the leafy tips with a u-mapped effector.
08 Create Branches
When the canopy looks sparse, build a separate, larger branch module out of the same assemblies and use that to decorate the tree. A new Simulate and Grow grown horizontally, a copied Assembly Decoration, and a little pruning give you a denser cluster.
09 Sim to Assembly
Convert the branch module you built into a reusable assembly with Rig to Assembly. Wire both of the Simulate's outputs, geometry and rig, into it, press play to check the instances animate, then use it to decorate the main tree.
10 Pruning
Use pruning and a Switch to control where growth happens. Prune the over-dense areas, keep branches off the lower trunk by switching the secondary Grow on above roughly two metres, and route it off the terminal shoot so the trunk doesn't end in a stub.
11 Nanite Export
Take the finished tree toward a game engine. Export it from Houdini as a Nanite Skeletal Assembly, ready to bring into Unreal.
12 Nanite Import
Bring the exported Nanite Skeletal Assembly into Unreal and get it standing in your scene.
13 Wind Config
Set up layered wind so the tree moves. Because the assembly is rigged, it responds to wind in engine.