UE4 hair groom alembic set up notes

Make sure to turn on the Groom and Alembic Groom Importer plugin, Niagara

Project setting: Support Compute Skin Cache

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Import setting

Rotate 90 degrees on x

scale Y to -1

Attach your groom to your character by adding your groom component to your actor

Then Drag and drop your groom asset to your groom component

For adjusting the hair

You can open the groom asset

go to the strands tab

manipulate the parameters there

use stable rasterization for the short hairs, that you can see through the hair to reveal the skin

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material for the hair

When creating material for your hair

utilize those attributes from your groom base color hair UV, seed, root UV, length... attributes

You can preview these attributes in the viewport of your groom asset

For materials set up

make sure the shading mode is hair

use of hair strands is turned on

access those attributes through the hair attribute node

another useful node is the hair color node

Material Examples

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Skinning

after done with setting up the material, it is time for binding the hair to your skin

right-clicking the groom asset, creating binding

Then just find your skeleton mesh to bind

Debug

r.HairStrands.debugMode 12

r.HairStrands.MeshProjection.Sim.Deofrmed.Triangles = "1"

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Simulation

open your groom asset, go to its physics tab

enable simulation

Play with those settings

It simulates the guides with Niagara System

r.HairStrands.StrandsMode =1

And don't forget to set up your collider in your physic asset first

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CVars

r.HairStrands.Voxelization.Virtual.VoxelWorldSize = "0.23"

r.HairStrands.Voxelization.Virtual.VoxelPageCountPerDim = "12"

r.HairStrands.Voxelization.Virtual.VoxelPageResolution = "64"

r.HairStrands.Voxelization.Raymarching.SteppingScale.Transmission ="6"

r.HairStrands.Voxelization.Raymarching.SteppingScale.Shadow = "4"

r.HairStrands.DOFDepth = "0"

r.HairStrands.DeepShadow.SuperSampling = "1"

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LOD System

Authoring in your DCC

Stand>Card>Mesh

or

Generate in UE4

use the plus icon on the right

for cards, you can try

procedural method (it is experimental)

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Reference:

https://youtu.be/__BScFPJy3E