Steering rack translation

The rack slides sideways as you steer, and the inner tie-rod ends ride it — so the tie rods pivot from a moving inner point instead of a fixed one. It’s the small detail that makes a steering rig look real. The role is Rack, and it lives at the front.

This animates the rack body + inner pivots. Your knuckles/steering rods still do the actual steering; this just makes the rack track it.

Parts → roles

Hierarchy

Front
├── SteeringRack         Rack · Slide Axis = lateral
│   ├── FL_TieInner          (no component — inner tie-rod point, ON the rack)
│   └── FR_TieInner          (no component)
├── FL
│   ├── FL_Hub               Hub · SteerCamber
│   │   └── FL_Knuckle       (no component — the tie rod's outer target)
│   └── FL_TieRod            Arm  (Pivot = FL_TieInner → Target = FL_Knuckle)
└── FR                       ... mirror of FL

The two inner tie-rod markers are children of the Rack — that’s the whole trick. When the rack slides, they slide with it, and the tie-rod Arms (which pivot about them) follow automatically.

What makes it different

• No steering input required. We never get a steering angle from the game — but the front hubs already yaw when the car steers. The rack reads the average of the two front hubs’ steer and slides from that.
• The slide feeds the tie rods for free. Because the inner pivots are parented to the rack, the existing tie-rod aim starts from the moved point — you don’t touch the tie rods at all.
• Slide Scale + Max Slide shape the motion. Slide is clamp(Slide Scale × average steer, ±Max Slide). Scale sets how much rack travel per degree of steer; Max Slide stops full lock from over-travelling the rack off its housing.
• Slide Axis is the rack’s lateral axis. In local space, which way does the rack run across the car? Usually 1,0,0.

Setup, step by step

1. Put a Hub on each front side (SteerCamber) — the rack reads its steer from these.
2. Put a KSuspBone on the rack mesh, Role = Rack. Set Slide Axis to its local lateral axis.
3. Add an empty at each inner tie-rod joint (FL_TieInner, FR_TieInner) and parent them under the Rack bone. No component on these.
4. Add an empty on each hub for the tie rod’s outer end (FL_Knuckle, …).
5. Rig each tie rod as an Arm: Inner Pivot = its *_TieInner (on the rack), Outer Target = the knuckle (on the hub), Telescopes ON.
6. Build Rig Hierarchy → Bake .ksusp. The report should say … and 1 rack(s).
7. In game, tune Slide Scale (and Max Slide) until the rack travel matches the steering.

Type gotchas

• The inner pivots MUST be parented under the Rack. This is the one non-optional step — if they’re under the hub or the chassis instead, the rack slides but the tie rods don’t move with it.
• Rack goes on Front. Its Corner field only picks Front vs Rear; “Build Rig Hierarchy” parks it on the front group.
• Wrong Slide Axis = it moves the wrong way (fore/aft or up/down). It must be the rack’s local lateral axis, not a world direction.
• Nothing happens usually means Slide Scale is tiny — it’s metres per degree, so 0.01 is a sensible start; go up if the rack barely moves.
• This isn’t the steering itself. The wheels steer because of your knuckle/steering-rod setup — the Rack only makes the rack body and inner tie-rod points track that steer.