Eyeball

The Demoman's eyeball.

Alyx's eyeball in Ep2.

A vortigaunt's largest eye. The iris covers its entire surface.

Eyeball is a property of $model. It consists of two components:

An 'eye white' surface on the model, with a unique material.
A dynamic iris decal that travels over the eye white material to simulate the eye looking in different directions.

Tip:An iris material can cover the entire surface of the eye if need be.

Parameters

Tip:The qc_eyes tool can help you manage the potentially confusing string of numbers needed for this command.

<name>: Name of eyeball, used to match eyelid rules. For humans, use righteye and lefteye.
<bone_name>: The bone which the eye is parented to, typically the head.
<X> <Y> <Z>: World location of the center of the ball of the eye.
<material_name>: Material above which the iris material will be drawn. Make sure every eye has a unique one!
<diameter>: Width of the eyeball when viewed from the front. Used to prevent the iris from rolling inside the head.
Note:The iris will travel in a circle even if the eyeball is oval. Your model's flex should accommodate for this.
<angle>: Default yaw offset (from directly forward) for iris. Humans are typically 2-4 degrees wall-eyed. Not setting this correctly will result in either your characters appearing cross-eyed, or if you've compensated by misplacing the ball of the eye, them not tracking side to side.
<iris_material>: Material to use as the iris texture. To do: This now appears to be a property of the eyeball material. Need some OB QCs to confirm.
<iris_scale>: Scale of the iris texture.

Hover your mouse over each value for its description.

$model "female_01" "female_01_reference_RE.smd" {
   eyeball righteye ValveBiped.Bip01_Head1 -1.261 -3.702 64.974 eyeball_r 1 4 pupil_r 0.66
}