s&box/field-guide
the symptom, in your words

"Kinematic movement that doesn't get stuck"

✓ verified on engine 26.07lane: Writing gameplayposted
▸ SYMPTOM
  • Player overlaps a collider (slide clip, building placed on top) and never moves again.
  • Every trace reports a hit; wish direction zeroes forever.
  • After noclip / teleport, exiting inside geometry traps the mover.
▸ CAUSE

Trace-based kinematic controllers have no body collider of their own — collision is entirely in the traces. If the current position is already inside solid, the next trace starts solid and a naive "hit → stop" loop permanent-entraps the player.

▸ FIX

Slide-trace pattern

snippet
var wish = Rotation.FromYaw(cameraYaw) * new Vector3(Input.AnalogMove.x, Input.AnalogMove.y, 0);
// … scale wish by speed * dt …

var tr = Scene.Trace.FromTo(pos, pos + wish)
    .Radius(radius)
    .IgnoreGameObjectHierarchy(go)
    .WithoutTags("player", "ghost")
    .Run();

if (tr.StartedSolid)
{
    // overlapped — ignore collision this frame so they can walk free
    pos += wish;
}
else if (tr.Hit)
{
    var slide = wish - tr.Normal * wish.Dot(tr.Normal);
    var tr2 = Scene.Trace.FromTo(pos, pos + slide)
        .Radius(radius)
        .IgnoreGameObjectHierarchy(go)
        .WithoutTags("player", "ghost")
        .Run();

    if (!tr2.StartedSolid && !tr2.Hit)
        pos += slide;
    // else stop / try secondary axis — your call
}
else
{
    pos += wish;
}

Trace API that works: .Hit, .Normal, .StartedSolid (also .Body, .HitPosition, .Shape, .Collider when you need prop pushes).

Placement / teleport hygiene

  • Forbid build placement within the structure's footprint of the player.
  • Never teleport "over" geometry by a fixed offset onto per-poly concave meshes — backfaces don't collide; you fall inside the shell with no StartedSolid. Down-trace from the apex, require walkable normal.z (e.g. ≥ 0.6), land on the hit.
  • Leaving noclip inside geometry: step the body up until a down-cast no longer starts solid (capped), then return to normal air/ground state.

Jump as pure visual/vertical state if you keep horizontal traces at fixed torso height — track _height / _verticalSpeed yourself.

▸ WHY IT WORKS

StartedSolid means the trace origin is already penetrating. Treating that as a normal wall hit zeroes motion forever. Ignoring collision for that frame (or ejecting) restores a free configuration so later traces can slide correctly again.

Verified on engine 26.07 — seen in a real project.
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