This week, my main focus was on hair interaction. I typically work on hair separately on the scalp or animal skin, such as human hair. I extract the scalp of the character, create the hair on the scalp, and then bind the finished scalp to the body. If it’s regular XGen hair, it can’t be interactively groomed in real-time. Therefore, initially, I chose to create the hair using regular XGen and then converted it into interactive grooming (Generate ➡️ transfer to Interactive Grooming). This step was crucial for preparing for the hair simulation.
Workflow:
- Create classic XGen hair ➡️ Convert it to interactive grooming XGen ➡️ Begin a series of hair simulation settings.
To create dynamic hair simulation, for example:
- I create a linear wire in the interactive XGen and add guide curves, enable dynamic simulation for the wire.
- I set the character as a passive collision object (under FX in the ncloth section), allowing the hair to collide and follow the character’s movements.
- Next, it is the configuration phase. In the Outliner, you’ll see hair system, nucleus. Hair simulation requires adjustments to three data sets: hair system (hair parameters), nucleus (collision calculation), and linear wire (guide parameters).
- In linear wire, you’ll adjust the Amplitude Ratio. The left side represents the movement amplitude at the roots, while the right side represents the movement amplitude at the tips. Smoothness is the degree of smoothness displayed as hair moves.
- In hair system, you can adjust parameters like friction (0.5) and stickiness (0.1) in collisions. These affect the delay and magnitude of hair movement. In the Dynamic Properties section, enable No Stretch to prevent hair from stretching unnaturally during motion. In the Forces section, you can find the Damp attribute, which also helps delay hair movement for a smoother result.
- Finally, in nucleus, in the Solver Attributes, you can adjust Substeps (16) and Maximum Collision Iterations (32) to improve the smoothness of collision effects.
Dynamichair Tutorial:
https://www.youtube.com/watch?v=MV_zpcwLRbY
In reality, there are many ways to address hair movement issues. I also found a method that involves binding skeletal animations to hair when binding bones to a hair plane. However, I didn’t use this technique in my current project. It’s shared here for reference:
Link：
https://www.youtube.com/watch?v=7IS_tnkO_oU
The process for animal fur is the same as above, but it’s important to note that animal fur is typically shorter, so the movement amplitude is smaller. Parameters should be adjusted accordingly, and not all parts of the fur need hair simulation to maintain a natural look.
Additionally, data from interactive grooming XGen can be exported as a resource (Description ➡️ Presets ➡️ Export) and imported in the same way. Data can be transferred to a model with similar or identical UV layout. Occasionally, exporting large volumes of hair may cause file crashes, but multiple attempts can lead to success.
That concludes the interactive grooming part of XGen. Hair preview effects: