Fixed Constraint

Locks the complete relative position and orientation of two bodies, or anchors one body rigidly to the world.

A Fixed constraint behaves like a weld. The body-to-body form preserves the complete relative transform that exists when it is created; the world form fixes one body around an explicit world-space anchor.

Syntax#

jolt_fixed(body_a, body_b, options=undefined)
jolt_fixed_world(body, anchor_x, anchor_y, anchor_z, options=undefined)

Arguments#

Options#

Methods#

Example: welded compound mechanism#

var carrier = jolt_box_create_dynamic(0, 0, 2, 2, 1, 0.5, { mass: 8 });
var payload = jolt_box_create_dynamic(0, 0, 3, 1, 1, 1, { mass: 2 });

var weld = jolt_fixed(carrier, payload, { collision: false });
if (is_undefined(weld)) {
    var error = jolt_get_error();
    show_debug_message(error.context + ": " + error.message);
}

The bodies retain their initial one-unit vertical separation and rotate as one rigid assembly. Their individual mass and inertia still contribute to the solver.

Example: fixed to world#

var sign = jolt_box_create_dynamic(0, 0, 3, 2, 0.25, 1, { mass: 4 });
var mount = jolt_fixed_world(sign, 0, 0, 3);

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.
• jolt_fixed_world() requires a finite anchor and one live body in the managed default world.
• A Fixed constraint has no limits, motor, spring, position or impulse getter in the managed API.
• Use a narrower constraint when any relative degree of freedom should remain available.

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.