Hotspot Mapping

Hotspot mapping gives surfaces their texture coordinates from a layout: the texture divided into tiles (a trim sheet or a hotspot texture). Every surface takes the tile that fits it best, so a texture made for it is laid on without placing any UVs by hand.

Setting it up

1. Give a material Chisel surface settings and press New Layout under Hotspot Layout, or pick an existing layout asset (Assets > Create > Chisel > Hotspot Layout).
2. Window > Chisel > Hotspot Layout (or Edit Layout) shows the layout over its texture:
   • Drag a line to move it.
   • Right click a tile, or press V or H over it, to split it vertically, horizontally, along a diagonal or into three triangles.
   • Delete removes the line under the cursor.
   • Import… reads a Chisel .json, a Valve .rect, an SVG or a colour mask image.
3. Select a tile to set its name, flags, border width and pixels per unit.

How surfaces are mapped

• It is live: every surface with the material is mapped as soon as you change the layout or the shapes, and a surface keeps its tile while it still fits.
• It maps what you actually see: the surfaces left after shapes are added and cut away.
• Tiles can have borders that keep their size while the middle stretches or repeats, and tiles can repeat.
• Tiles don't have to be rectangles: triangles, other shapes and tiles with holes work too, and the texture keeps its up direction.
• Round surfaces are mapped too, and a material can have variants with other tiles.

Per surface

• In the UV tool a surface can keep one tile (Hotspot Tile), or take another of the tiles that fit it equally well, or another of the material's variants (Next Variation, Alt+N in the scene view).
• A hotspot surface's offset, density and rotation are its Translation, Scale and Rotation; UV Move, UV Rotate and UV Scale change them.

A layout's tiles are also the images Decals and Trim Decals can use.