Hair card budget tables: texel density and triangle counts

Hair cards are thin textured strips that stand in for strands on game and stylized characters. Two numbers decide how a card hairstyle looks and what it costs: how many texture pixels land on each card, and how many triangles the whole style uses. These tables give both, so you can pick an atlas size and a card count before you start placing cards.

Assumptions: the hair texture is an atlas split into equal columns, each card uses one column-wide cell across its width, and a card is a single strip of quads: segments quads along its length, 2 vertices per row, 2 triangles per quad. The numbers are plain arithmetic from those assumptions, not measurements of any engine.

Table 1: atlas cell width and texel density

Cell width in pixels is the atlas size divided by the number of columns. Texel density is that cell width spread across the card's width. Rows do not change these figures; they only set how many cells you get.

For another card width, divide the cell width by the width in cm: a 256 px cell on a 2 cm card is 128 px/cm, on an 8 cm card 32 px/cm. Narrow cards on a wide cell look sharp but you get fewer distinct strand textures per atlas.

Table 2: vertices and triangles for a whole style

Each card has 2 × (segments + 1) vertices and 2 × segments triangles. More segments let a card bend smoothly; more cards fill gaps.

Example: 200 cards at 8 segments is 3,600 vertices and 3,200 triangles before any extra layers or a scalp mesh.

Braids as tubes

A 3-strand braid built from round tubes costs far more than a card. Each strand with sides around and segments along has (segments + 1) × (sides + 1) vertices (one seam column for the UVs) and 2 × segments × sides triangles. A braid of 3 strands at 60 segments and 8 sides is 1,647 vertices and 2,880 triangles, about the cost of 180 cards at 8 segments.

Making the cards from curves