In this article, we'll be explaining what hair bounce is, and how to make your models' hair bounce naturally.
Table of Contents
- What is Hair Bounce?
- Setting Hair Bounce
- What are Bone Groups?
- What are Bones?
- How to Set Hair Bounce
- Adding Bones
- Bones Parameters
- Other
What is Hair Bounce?
On VRoid Studio, you can set "Hair Bounce" for each chunk of hair.
By setting hair bounce for your character's hair, they will have a more natural look when moving, or maybe even walking or running.
In preset hair items, hair bounce has been already set. You can check how the hair on your model moves at any time, by going to Photo Booth and trying out some pose or animation.
Setting Hair Bounce
In order for hair to move, you first need to group them into units (chunks of hair) and give each of these groups what we call "bones".
You can let the software automatically group hair and set bones, or do it manually.
What are Bone Groups?
Each unit of hair, each group that will have their bounce settings, is called a "Bone Group".
Each bone group has an "axis" going through it, which is where the bones are. Bone groups for hair with bones already set will display in a different color. When you select a bone group, you'll see the position of the bone axis.
What are Bones?
A bone is a single unit that decides how the hair will move. Like human bones, each of these bones is connected by some kind of joint. This is where the hair will bend. Think of these as a finger with more knuckles or an arm with more elbows.
The fewer the bones, the more mechanical the movement will be, while more bones will result in more fluid movement, much like a snake moving through the grass.
It's a balancing act. On the one hand, more bones will help give movement and charm to your character. On the other hand, too many bones will be demand more processor power and may be difficult for the software to process.
How to Set Hair Bounce
Select the hair you want to set bones for and click (or tap, on the iPad) on the "Set Hair Bounce" button on the right panel.
Adding Bones
There are two ways to add bones.
- Automatically setting bone groups, axis, and parameters.
- Creating individual bone groups and setting axis and bones count manually.
Automatically setting bone groups, axis, and parameters
1.Select the hair category you wish to add bones to from the list on the left hand of the screen. Next, set the number of bone groups to generate via the slider (range: 1 to 30).
2.Click (or tap, on the iPad) on "Auto-generate Bone Group".
3.The software will generate as many bone groups as you set on the slider.
4.If you're unhappy with the bounce results, select each group from ”Grouped Hair" and adjust them using the parameters panel on the right.
For more details on each parameter, take a look [here].
Creating individual bone groups and setting axis and bones count manually
1.Select a group listed in "Ungrouped Hair".
2.Select the (chunk of) hair you want to add bones to, and click (or tap, on the iPad) on "Create Bone Group".
(You can add bones to single hair chunk or to groups of hair as well.)
3.Select the generated hair group and adjust the parameters on the right-hand panel.
For more details on each parameter, take a look here.
Bones Parameters
Move Axis to Group Center
Click this button to reset the bone axis at the center of the group.
Bones
The more bones, the wider range that hair will sway.
Range: 1 to 16
Fixed Point
This is where the first bone is placed (the one closest to the scalp). The start point for the first bone moves towards the tip of the hair as the value increases, making the rest of the hair (from scalp to fixed point) stiff. With a smaller value, the fixed point will move closer to the head, making the hair sway over all its length.
Range: 0.01 to 0.99
Stiffness
Hair gets stiffer as the value increases.
(The image below shows both ends of the range. Left is 0, while right is 1.)
Range: 0 to 1
Gravity
The gravity applied to the hair gets stronger as the value increases.
(The image below shows both ends of the range. Left is 0, while right is 1.)
Range: 0 to 1
Hit Radius
The collider (an invisible object determining the hit radius) gets bigger as the value increases, preventing hair from intersecting with the face and other body parts.
(The image below shows both ends of the range. Left is 0, while right is 0.1)
Range: 0 to 0.1
Other
Selecting Hair to Determine Bone Axis for
If you want to axis to be not at the center of a bone group, but on a certain piece of hair, or group of hair, select that hair and click (or tap, on the iPad) on "Set Hair as Axis".
Managing Bone Groups
Right-click (or tap twice, on the iPad) on a bone group to display the drop-down menu with the following actions:
- Rename Bone Group
- Toggle Bone Group Visibility
- Delete Bone Group
Remove Hair from Bone Group
To remove a chunk of hair from a selected bone group, select that hair and click (or tap, on the iPad) on "Remove Hair from Bone Group".
Move to Selected Group
To add a new chunk of hair to an existing bone group, do as follows:
1.Select the bone group you wish to add hair to
2.Select the hair you wish to add
3.Click (or tap, on the iPad) on "Move to Selected Group"
Things to Note
If you edit a hairstyle for which you had already set hair bounce, the hair bounce and bones will not be edited.
If you edit a hairstyle for which you had already set hair bounce, open the hair bounce editor once again, select the edited bone group, and click (or tap, on the iPad) on "Move Axis to Group Center" to adjust the axis with the edited piece of hairstyle.
The bones direction follows the direction of your stroke when you created that chunk of hair with the brush tool.
(Left shows hair drawn downwards; right shows hair drawn upwards.)