Atlas Workflow

The atlas tools take a foliage atlas, one image with many leaves or twigs laid out on it, and turn each piece into its own mesh with the atlas material on it. The atlas can come from a photo shoot on a backdrop, a scan, a hand-painted texture or a store kit.

An atlas usually comes as a set of maps: colour, alpha, roughness, height, normal and subsurface. Atlas Material on its own can derive the ones you don't have from the colour; the Atlas Wizard reads each channel from its file, so give it at least a colour and an alpha map.

Atlas Wizard

Atlas Wizard is the place to start. You can find it in the toolbar's Import menu. Give it the atlas maps under Source Textures, and it cuts the pieces out, meshes them and lays them out. It opens with the Summer Birch example atlas loaded, so you can see a result straight away.

Mesh Settings set how dense the mesh is along each piece's outline (Border Edge Length) and inside it (Inner Edge Length). Threshold is the alpha value the outline is traced at.

Inside, the wizard runs Atlas Material, then Atlas Mesh, then Atlas Layout. It returns one packed output, with the layout preview packed inside it. In the shipped Simple_Tree.hip example, that output goes into the first input of a Clusters Decoration. The wizard's own input is optional: curves wired into it reach Atlas Mesh as the leaves' spines, and the example wires a skeleton there.

The Atlas nodes

When the wizard doesn't give you enough control, use the nodes it is built from, or the extra ones beside them:

• Atlas Material reads the atlas maps. For each channel you choose File (use the map you give it) or Cops (derive it from the colour). Alpha can come from a file, the image's alpha channel, a chromakey, a white background, or segmenting the colour. See Atlas Materials.
• Atlas Trace traces each piece's outline from the alpha, with a Raster or Vector Trace Method, so the mesh follows the leaf instead of sitting on a square card.
• Atlas 3D bends a flat piece into shape by its distance from curves wired into its second input, through a Shape ramp with optional noise.
• Atlas Emboss shapes the surface of a piece from its border, spine and vein curves, each with its own scale, falloff and noise.
• Atlas Layout names each piece, sets its Type (Leaf, Twig or Custom), straightens it, and shows the pieces either overlaid or spread out (Display Alignment).

Atlas Mesh, which the wizard uses for meshing, is hidden from the Tab menu.

Atlases on store assets

Store kits that come with their own assemblies already have their leaves meshed. For those, you only need the atlas texture, and it goes on through a Surface Resource. See Atlas Materials.

Status

The atlas tools are experimental and less developed than the rest of Natsura. Individual nodes and parameters may change.