Github things

In Blender, the hair particle system is a collection of splines. Splines have control points. Everyone has seen the smoothness of bezier curves, etc. Real-time representations usually quantize each strand into discrete points - I do it in my Blender exporter. The number of points per strand is customizable and depends on the hairstyle. Short hair can get away with as little as 3 points.

For example, my Frostbitten hair WebGPU uses 16 points per strand. Increasing the number of points provides a smoother look at the cost of complexity. The rendering performance hit depends on the selected technique. As I’ve discovered, in Frostbite’s tech, the cost evaluation is quite complicated. While you have to process more segments in the tile pass, the fine pass often reaches enough pixel/tile “opaqueness” to return early during the processing. This optimization happens regardless of strand count.

The question now stands: “How to turn connected points into pixel coordinates?“. We will be using billboards that have width controlled by fiberRadius parameter. Increasing fiberRadius makes each strand wider.