Hair and Fur

Description

Hair and Fur Geometry Nodes Assets are a new type of asset based on the new curves that you can apply in Mesh Objects.

When you apply a hair asset, a geometry nodes modifier is applied to the target object and a new curve empty object is parented to it with a 2nd geometry nodes modifier.

In the Target Object modifier you will find the parameter for the World Scale
In the Curves Object modifier you will find all the parameters related to the curves/hairs

Object Proportions and scale

The world scale that you set in the target object is a multiplier for the entire tool, if you increase the scale, the hairs radius will increase, the space between them, etc..
If you want all your objects look like they are in the same scene, you set the same value on each object.
if you want a 1M object to look exactly like a 2M object, then you set the Scale to 2 in the 2M object and to 1 in the 1M object. So basically you can use the objects dimension as a guide in this case.

The Material

Both surface of the target object and hairs, share the same material. This material can be accessed by selecting the target object. Here you can change the parameters related to the material.
There are inputs and parameters for the skin and the hairs. A custom coordinates node can be switched from UVs to Custom. If you want to use an image texture you can switch it to UV (value 0). For procedural materials, it’s better to use the Custom coordinate.

Animation and Modifiers

Both materials and hairs are compatible with rigs and modifiers that deform the object.
UV Map is required to hold hairs in place during deformations and animations
Direction and Wind are not compatible with deformation, animation and shape keys because hairs are looking for the shortest angle to the direction specified and that may change while deforming the mesh.
By setting those 2 masks to 0 you will be able to animate the object with the hair correctly attached to the object and with no flickering.
You can always use sculpt mode in the curve object to comb and adjust the length of the hair while you are not using hair direction.

Best result

If a modifier deforms the objects geometry the tool will work a lot better if you apply them (bevel, subdivision surface).
It will also look better on more organic shapes, beveled edges look better than sharp edges:

Adapt in different conditions

The skin (or the target object) and the curves/hairs usually have the same material to achieve a good result with less density. This may change depending on the object shape (sharp corners expose the surface more), the lighting and contrast with the background. Increasing the render density may help cover the surface better.

Sculpt your own Hair

You can use the curves that the tool automatically generates or you can select the curve object and enter Sculpt mode to add your own curves. This will completely replace the generated hair and you will be able to adjust length, comb, etc. If you use your own curves, I recommend you to set the mask in “HAIR DIRECTION” to 0, so you don’t override the combing. The material and other parameters like frizz and wind will still affect the curves you create manually.

Vertex groups and other attributes

Masks and some other parameters allow you to click the “Input Attribute Toggle” button and use an attribute like a vertex group to drive things like density and other parameters.