Trunks & Meshing

The simulation grows a skeleton: a hierarchy of internodes carrying attributes, not yet a renderable mesh. Meshing is how that skeleton becomes geometry, the woody trunk and bark as much as the foliage, and in Natsura you express it through decorations.

A decoration is the contact point between the simulation and the meshing. It is where you say what meshing you want, and where, by assigning a meshing process directly to parts of the structure using the same UI that defines growth. Assign a surface decoration to a Grow and it skins those branches into trunk and bark; assign an Assembly Decoration and it places foliage on them. The meshing travels with the structure rather than living in a tangle of SOPs wired downstream of the Simulate.

Visual pending.

Where shaping meets meshing

Shaping produces the structure; decorations express the meshing onto it. The decoration is the seam between the two. Most decorations are pure post-process: they run after the skeleton is grown, which keeps them fast to iterate, since you can change the look without re-running the simulation. A few, like certain trunk decorations, can push information the other way and feed back into growth, so a defined or scanned trunk can guide the branches and roots that grow from it.

Trunks: the woody structure

The trunk and bark can come from two directions, and they meet in the same pipeline.

• Grown and skinned. A Surface Decoration or Trunk Decoration turns the grown skeleton into watertight trunks and branches, layering bark detail, height, and noise driven by the internode attributes.
• Brought in from a scan or sculpt. When a shot needs hero fidelity, you can bring real geometry in (photogrammetry, a ZBrush or Blender sculpt, a LiDAR scan, a hand-modelled trunk) and grow procedurally from it. Natsura chops the raw mesh into reusable parts, and procedural branches stitch onto it with a Bake step that blends tiling textures at the boundary where growth meets the static geometry. This whole scan-to-growth route, including the point-based handling that keeps very high-poly inputs out of the viewport, is the Scans feature.

Use a scanned or sculpted trunk when a shot calls for hero quality or has to match a specific real tree; use pure procedural geometry for mass forests and performance-critical, real-time work.

The kinds of decoration

At the concept level there are a few families. The Decorations feature page covers the full set and how each works.

• Surface and trunk. Skin the skeleton into watertight trunks and branches, layering bark detail, scan data, or procedural noise.
• Assembly. Place pre-rigged library pieces (leaf clusters, branch chunks, fruit) onto the tree by trait matching. The default for foliage; see Foliage & Instancing.
• Cluster. Deform flat meshes to follow a branch, for the cases where the input is a static mesh that should bend along a curve.
• Utility. LOD, proxy, and collision stacks, swapped in and out without touching growth, so one graph carries many representations.

A meshing language you can extend

Each decoration is a compiled SOP graph stored as geometry, so the Simulate can invoke it efficiently, and so it stays portable: a decoration can be saved and loaded in another scene and still evaluate. Because they are attribute-driven rather than tied to node paths, parameter changes are treated as data and stay cheap, while only a structural change forces a recompile.

Natsura ships a library of decorations, and it will keep growing. When the library doesn't cover what you need, you can build your own from Core Decoration: a network that consumes the skeleton and its attributes and outputs the meshes you want. It is technical work, biased toward verbs and VEX, and there are more templates and examples to come. Authoring decorations as APEX graphs directly is planned for the longer term.

Surfacing the result

Meshing produces geometry; materials and texturing give it a surface. Bark materials, leaf atlases, two-sided leaves, and baking all sit on top of the meshed result. See Materials and Bake.

Related

• Scans, the scan, sculpt, and high-poly workflow in depth.
• Decorations, the technical reference for the meshing layer.
• Materials and Bake, surfacing the meshed geometry.
• Foliage & Instancing, the foliage side of meshing.
• Simulation and Shaping, what produces the skeleton meshing runs on.