Content Dev:CC 3.4 Hair Soft-Cloth Settings

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Main article: CC Asset Production.

Weight Map Production

The physics map for the hair must be pure black for the roots of the hair (10 pixels recommended area) so that the hairs do not detach from the scalp when soft-cloth physics is enabled.

Cc34 hair weight map workflow.png

Some best practice to follow when drawing the physics weight map:

Gray-scale Maps Black(0, 0, 0) Gray (1-254) White (255, 255, 255)
Dynamic Static Semi-dynamic Dynamic
Collision No collision settings with mesh intersection determined by skin weights. Inaccurate collisions and easily intersects with other meshes. Accurate collisions and very unlikely to intersect with other meshes.
Modeling Maintains shape well. The shape is affected by the depth of the gray-scale weight map. Does not maintain shape well at all.

Important Notes on Soft-Cloth

Juddering from Soft-cloth Inter Collisions

Cc34 hair project menu.png

Collisions between two soft-cloth meshes can cause both objects to judder. iClone can handle two or more soft-cloth body collisions when Project > Global Physics Settings > Soft Cloth > Soft vs Soft Collision is enabled, e.g. for a character with skirt, tie-waist shirt, and dynamic hair. The higher the Margin value, the easier it is for the soft-cloth parts to shake out of control.

Maintaining Structure of the Hair

Structure and shape for curly hair is notoriously difficult to maintain with soft-cloth physics enabled. There can be a big visual difference between static and dynamic hair, especially for long and curly hair types where overall styling can be lost. Curly hair has a tendency to penetrate into each other due to low collision accuracy. One must decide to choose either style or physics accuracy.

Cc34 hair physics on off.png

Dealing with Dynamic Mesh Structures

Mesh with thickness and soft-cloth enabled will tend to collapse upon itself. Therefore, it is recommended to use Spring physics for braided and curly hair for the best results, however, Spring Hair does not have collision detection.

Hair Lying on the Chest

Hair lying on the chest can easily behave erratically when physics is turned on as it is likely to be thrown behind the character's back when the character is animated.

Collision Count Limitation

According to specification dated August 3rd, 2015, the number of collisions on a character should not exceed 16. Although the character’s collision is limited to 32, the collision will start to be inaccurate beyond 16. You should set the position of the collisions according to the areas with soft-cloth applied.

Cc34 hair parts.png

It is recommended that the basic composition of hair can be divided into the following structures:

1) Base (scalp)
2) Front (bangs)
3) Top (crest)
4) Back
5) Chest (hair lying on the chest)

The hair parts can be divided according to your needs. Organized from inside out, there are about 3 to 4 layers, with 4 being the usual limit. More soft-cloth settings and weight maps can make the hair harder to manage.

Cc34 hair poly count comparison.png

Soft-cloth weight maps needs to be "flooded" to encompass each individual hair strand (left).

Commonly Used Hair Soft-cloth Parameters

Inertia The degree to which an object bounces back and forth when it is shaken. The higher the number, the greater the rebound effect Tether Limit, Stretch, Bending can be used interchangeably
Tether Limit The length of the extension. The upper right of the picture below shows that when the Tether Limit is 5, the hair is stretched; the lower right is when the Tether Limit is 1, the hair remains the original length.
Stretch For extended length, the Stretch effect is less obvious on the hair. Blending needs to be turned on at least 1 to make Stretch and Tether Limit have an effect.
Blending The effect is less obvious on the hair, and the object must be collided to show that the larger the effect value, the harder the smaller the value, and the softer
Damping The degree of friction of the object, the higher the value, the higher the friction, the slower the falling speed (Ex. I hope that the hair should be a little heavier, and not as slippery as silk when sliding on the body)
Drag The degree to which the hair is affected by air is more effective when the wind parameters are turned on. The higher the value, the greater the impact, and it is more uncontrollable when pure action is performed (Ex. I hope that when the wind blows, the hair will be affected by air fluctuations)