Cone Constraint

Keeps a shared anchor together and limits swing to a circular cone while leaving twist around the axis free.

Cone is useful for pendants, simple ball joints and links that may tilt by a maximum angle but do not need twist limits. For elliptical swing, twist limits or angular motors, use SwingTwist instead.

Syntax#

jolt_cone(body_a, body_b, anchor_x, anchor_y, anchor_z, axis_x, axis_y, axis_z, max_angle, options=undefined)
jolt_cone_world(body, anchor_x, anchor_y, anchor_z, axis_x, axis_y, axis_z, max_angle, options=undefined)

Arguments and options#

Angular behaviour#

• The current axis may swing away from the reference axis by at most max_angle.
• Relative twist around that axis remains unconstrained.
• A limit of 0 degrees locks swing; 180 degrees is effectively free swing.
• The public API uses degrees and converts to Jolt radians internally.

Methods#

Example: hanging lamp#

var lamp = jolt_box_create_dynamic(0, 0, 3.5, 0.7, 0.7, 1, { mass: 3 });
var joint = jolt_cone_world(
    lamp,
    0, 0, 4,
    0, 0, -1,
    35
);

Body-to-body example#

var joint = jolt_cone(upper, lower, 0, 0, 4.5, 0, 0, -1, 45, {
    collision: false
});
joint.set_limit(30);
var swing = joint.get_angle();

Errors and lifecycle#

• Body-to-body creators require two different live managed JoltBody values in the same managed default world.
• At least one connected body must be movable; native Jolt rejects an unsupported static-static pair.
• Constructors return a managed JoltConstraint on success or undefined after a validation/native creation failure.
• Destroying either attached body automatically destroys and invalidates the constraint before releasing that body.
• Read jolt_get_error() after a failed creator or method when the values may be untrusted.
• Anchor and axis components must be finite, and the axis must have non-zero length.
• max_angle and runtime limits must remain between 0 and 180 degrees.
• Cone exposes no motor or spring. Use SwingTwist or SixDOF for powered angular control.

Verified operation contracts#

These contracts distinguish units, return values, errors and lifetime according to the current implementation. Check results: false, 0 and undefined can mean different things for different methods.