Hair and grooming in Houdini
Hair and grooming
preparing head geo
add head geo and remove existing hair with sculpting (c4d) fix texture and paint skincolor into hairparts in basecolor and normal map create a copy of the head and fix topology with vdbs or quad remesher (use this for hair not the base model)
adding hair
select test geo -> hair utils -> Create guides this create the Guide groom node adjust density: 2000 change dropdown to: skin attribute then click Paint Density Attrib button (next to density attrib field!) this creates all the nodes to paint the attribute
remove all existing guides
shape: Fill hold crtl and click onto geo (this should fill whole geo with purple)
paint areas to fill with guides
shape: surface paint some hair areas (use mouse wheel to increase/decrease radius) hold control to delete, shift to smooth
adjusting length
select Guide groom node Guide process (shelf) -> Set guide length length: 0.3 change dropdown to skin attribute lenth attrib: density while guide process node selected guide process (shelf) -> initialize guides then rotate red line (scheitel) while guide process node selected guide process (shelf) -> curve advect then draw to give hair some parting Guides brushes (shelf) -> screen brush and paint nice shapes Guides process (shelf) -> frizz guides for more zigzack
adjusting segments
go to obj/ level and select guide groom node Segments: 16
reload cache
Guides brushes (shelf) -> Recache strokes
create the hair
Hair utils (shelf) -> generate hair then select guide groom node and press ENTER in hair generate node add the hair material (rs_hair) density: 20000 influence radius: 0.04
to delete some short hairs
go into guide groom select last guide process node and then start deleting single guides
create clumping
go into hair generate node add hair clump node (plugin: hairs skin skinvdb) blend: adjust clump size: adjust crossover: 1 change to fractal clumping tab and adjust iterations
cutting straight lines
go into hair generate node (select clump node) guides brushes shelf -> cut hair then just cut away :D
adding some gravity to make it look more natural
select guide groom node hair utils (shelf) -> click _simulate guides this creates guide simulate node (press play to see hair falling) select guide simulate node vellum solver tab substeps: 5 vellum constraints tab -> bend stiffness: 10000 check freeze frame: 30 (to cache result)
rendering hair
in hair generate node: material: rs_hair general tab density: 50000 thickness tab thickness: 0.0003 (press recache strokes afterwards) render tab hair generation: use SOP geometry