LEARNING GUIDE

Portal physics and collision: keep hypotheses separate from authority

draft illustrative

Origin: original-commentary · review: draft · snapshot: 3ba1c69afc74a97f-7fcd0798fd6ea455

The reference exposes useful physics and trace declarations, but it does not

declare a portal traversal API. This note is deliberately a planning guide for

bounded probes rather than a claim that a particular relocation recipe works.

Physical continuity

Use one authoritative rigidbody state. A crossing detector should be sampled in

the physics/update phase that owns that body, using a stable reference point and

the actual shape. If the body is relocated, record pose, linear and angular

velocity, centre of mass, sleeping state, interpolation and network ownership

before and after the operation. A destination-side visual duplicate is not a

second collider and must not become a second authority by accident.

The indexed source and metadata show related body, velocity, joint and sleep

surfaces. They do not prove that a game can write every one of those values, nor

that compound shapes or joints can straddle two spaces.

Test collision and traces separately from the visual aperture. A per-query

filter or a contact hook, if actually exposed, must be scoped to the crossing

and restored immediately. Ignoring an entire backing wall is not equivalent to

opening one aperture, and stencil or depth clipping has no collision effect.

Start with an off-centre rotating box and no joints. Compare slow, normal and

fast crossing in both directions, stopping on the plane and changing crouch

shape where relevant. Then add contacts, joints, fog and recursive views as

separate dimensions. Record a pass/fail result for pose, velocity, contacts,

authority, interpolation and re-entry suppression; do not call the experiment

runtime verification until it runs in the installed engine.

The collision-filter and rigidbody steps in the workflow catalogue are marked

metadata/source-only or unresolved. Exact public game availability, fixed-step

ordering, contact modification and network ownership remain questions for an

installed-build probe.

Evidence hash: 9cfdcd4a94162cb035e48689fb4cccb9ab8fe0c65db7a9db1e9c90aa3e832b5a
Compile/runtime verification: illustrative