Foliage Cards
Alpha-textured planes that form leaves and plants
Also known as: Foliage card · Leaf cards · Alpha cards vegetation · Billboard foliage · Tree leaf cards · Plant cards
Definition
Foliage cards are flat polygons with an alpha-textured image of leaves, branches or whole plants, used to build vegetation cheaply. A tree is made of a trunk mesh with clusters of leaf cards arranged in volume, grass is made of cards with blades painted on them, and distant trees are reduced to billboards. The cards use a masked material, and two-sided shading so both faces show, and they are placed and rotated to hide their flat shape.
In production
Paint or render the leaf textures with clean silhouettes, color variation and enough padding, and shape each card to follow the leaves to reduce transparent pixels and overdraw. Place cards in layers with varied orientation and size, and bend them slightly. Add wind with vertex color and World Position Offset. Use LODs that reduce the number of cards and finish with a billboard for distance.
