Trunks & Meshing

The simulation grows a skeleton: curves made of internodes that carry attributes, not yet a mesh you can render. Meshing turns it into geometry, the trunk and bark as much as the foliage, and in Natsura it is done with decorations.

Decorations

A decoration is a compiled program, one that ships with Natsura or one you build, that you assign to a Grow to say how the part of the tree it grows is meshed. Choose one from the toolbar's Decorate menu with the Grows selected, or drag a decoration you already have into an empty slot under Decorations on the Grow. This saves you building a network after the Simulate to process what it grows, and the meshing stays with the part of the tree it belongs to.

Every new Grow comes with a Trunk Preview decoration, so you see a rough mesh straight away. Set Output to Skeleton on the display toolbar to see what the simulation grew before any meshing.

Decorations run after the skeleton has grown, as a post-process. Changing a decoration usually doesn't grow the tree again. The Decorations page covers how they work.

The decorations

• Surface Decoration sweeps the skeleton into trunks and branches. Its own effector stack can displace the surface.
• Trunk Decoration places a scanned or sculpted trunk on a Grow, for procedural growth to extend.
• Assembly Decoration places rigged parts from a library, such as branches and leaf clusters. It is the main way to build foliage; see Foliage & Instancing.
• Clusters Decoration fits parts along the branches, bending them to follow each one.

A Grow can carry more than one decoration, such as a Surface Decoration for its bark and an Assembly Decoration for the parts on it.

Trunks from scans

When a tree needs a particular trunk, such as a scan, a sculpt or a hand-modelled mesh, you can bring it in and grow from it. Import Highpoly loads the mesh and picks the profiles, the open ends that growth extends from. Create Graft Mesh builds a lighter mesh with room for the extensions, and sets the tiling textures and the blend region where procedural growth meets the scan. Bake bakes the scan's detail onto that mesh, with those textures blended in. The result goes into a Trunk Decoration on a Grow, and other Grows extend it, meshed with a Surface Decoration.

Scans can be very heavy, so the scan tools show a point cloud in the viewport and only work on the full mesh when they cook. The Scan Workflow covers the whole route.

Your own decorations

When the shipped decorations don't cover what you need, you can build your own. Inside a Core Decoration you build a SOP network that can be compiled: it takes the skeleton and its attributes and outputs the meshes you want. You can then wrap it in your own HDA and call it what you like. It is technical work; see Building Your Own Decorations.

Materials

A Surface Decoration takes its material from a Surface Resource wired into its first input, which holds the bark textures. Assembly parts take theirs from the Assembly Resource. See Materials and Baking.

Status

Core Decoration is hidden from the Tab menu in 0.7.3. Create Graft Mesh's uvscale has no effect in 0.7.3, and Bake writes colour, normal and height maps only. Trunk and surface meshing are the main focus of current work. Clusters Decoration 2.0 is the start of an upgrade to work with mapping and effectors; Clusters Decoration 1.0 stays for older scenes.