I ask this question because I am trying to find a way to convert a collection of hair cards from a game into a particle hair system. I tried using the hairnet addon, but It wasn't working for me. I want the hair particles to grow from the hair cap. Below are pictures of the hair cards as a whole and a single one of the hair cards in edit mode if it helps.
You can use the HairNet addon to convert hair cards to hair particles.
the hair cards can be directly used as Sheets for the HairNet addon. They may need some preparation to fulfill a few requirements:
- the sheets must have a mesh of quads. If the hair cards are made of tris you can convert them to quads with Face → Tris To Quads (Alt+J), in Edit mode.
- the hair cards need at least 3 vertical edges. A vertical edge will be converted to a hair guide (particle/strand). Add and apply a Subdivision Surface modifier if needed or add some edge loops manually (Ctrl+R)
- all hair cards in one object must have the same number of vertical subdivisions. You can use the Select Islands by Face Count addon by Stan_Pancakes to separate the hair cards into separate objects with Separate By Face Count
if the hair cards fulfill these requirements you need to Add Seams to the edge that will be the root of the hair. With L you can select the hair cards and hide (H) them after you have added the seams.
use Sheets in the HairNet addon to create the particles.
set children type to Simple
Don't forget to "touch" the generated hair in comb mode as described in the addon.
Note: There is currently a bug that makes the particles of existing hair particle systems move down on the Z-axis. To prevent this just disable the viewport visibility (monitor icon) in the Particle System Properties or the Modifier Properties for all existing particle systems before you add another with the addon (Blender 2.9x and HairNet 0.6.x are affected).