Atlas Material

Atlas Material builds the leaf material from an atlas's textures. It reads the colour image, makes an alpha from it or from a file, and for roughness, height, normal and subsurface either reads a file or works the channel out from the colour and alpha in Copernicus. The output is a flat card wearing that material, which Atlas Trace cuts the leaf shapes from. It needs no input. Atlas Wizard runs it as its first step.

Channels

Colour and Alpha are under Material; Roughness, Height, Normal and Subsurface have folders of their own.

Colour is read from its file by default. Under Alpha, a menu picks how the cut-out is made: Chromakey keys out a background colour (set with Hue/Saturation under Chromakey Settings), White Background keys out white, Segment separates the leaves by connectivity (with its own Threshold under Connectivity Settings), Alpha Channel uses the colour image's own alpha, and File reads an alpha image of its own. Erode/Dilate, under Alpha Settings, shrinks or grows a cut-out made from the colour; it is hidden when the menu is on File.

Roughness, Height, Normal and Subsurface each have a Derive menu. File reads the image you give it, and Cops (the default) derives the channel from the colour and alpha. Height Scale and Normal Map Scale set the strength of the height and normals.

Writing the textures

Each channel's Render button writes that channel to disk, and Render All writes them all. Files go to Cache Directory ($HIP/Natsura/Cache by default), named from Name with the channel as a suffix (_colour, _alpha and so on), in tiff, tga or png.

With Override Material Assignment on, each channel under Material Assignments chooses whether the material uses the source image or the rendered file (Source or Output). Output is the default, so render the channels first.

Atlas Materials covers how these maps shade the leaves, including the two-sided setting leaves need.

Status

The atlas nodes are experimental, and their parameters may change.