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Bolt Runs Unexpectedly in Carts After Switching from Camera Orbital — E-Stop Required

Target Tracking Ongoing Bolt family BOTH

Summary

When switching from Camera Orbital tracking mode to Target Tracking On while in a Cartesian mode, the Bolt may start moving unexpectedly — driving toward a computed target position that does not match where the rig is. Pressing Spacebar does not stop the movement in time; the E-stop is required. This is a safety incident — the rig motion is uncontrolled and poses a risk to camera, talent, and crew. Multiple operators have reported this behaviour across rig types and Flair versions.

The clearest WhatsApp incident was reported on Flair Classic 7.25 build 28 Mar 2024. The operator had no keyframes defined, the track was disengaged, and in one related report no HHB or external controller was connected. That makes this distinct from ordinary joystick drift.

Symptoms

  • Tracking mode was Camera Orbital (or other Carts-active mode)
  • Operator switches to Target Tracking: On while in any Carts view
  • Bolt immediately begins moving — not a programmed move, not a GOTO — just drifting/running toward a computed position
  • Spacebar does not stop the motion
  • E-stop must be pressed to halt the robot
  • After reset, the rig is repositioned and may have moved significantly
  • Turning Carts Off stops the motion in the reported cases
  • The problem can appear intermittent: operators reported it across multiple Flair versions but could not always reproduce it on demand

Root Cause

Not fully confirmed. Most likely: when switching from Camera Orbital to Target Tracking On while carts are active, Flair computes a new target position from the current focus distance (which may be at infinity or an invalid value). This produces an immediate large Cartesian error, which the kinematics engine tries to correct by driving the axes — resulting in uncontrolled motion.

The issue is related to the focus-at-infinity problem (see TT camera orbital drift carts), but the consequence here is more abrupt — a fast, unexpected move rather than a slow drift.

Other suspected contributors from the chat:

  • Camera Orbital + Cartesian mode active at the same time
  • Focus or target distance at infinity
  • A Cartesian adjustment in Locked View
  • HHB/controller setup state in some reports, though this was ruled out in at least one related case
  • Stale project state; in less severe drift cases, restarting Flair or power-cycling cleared the behaviour

Workarounds

Emergency stop sequence

If the rig starts moving by itself:

  1. Press E-stop immediately if motion is fast or near people/equipment.
  2. If there is time and the rig is clear, click Carts Off; this stopped the motion in the reported cases.
  3. Disengage the robot before changing tracking modes, focus, HHB setup, or lens setup.
  4. Save a copy of the job for fault reporting before rebuilding it.

Safe mode switch procedure

To safely switch from Camera Orbital to Target Tracking On:

  1. Turn off Carts before switching tracking mode.
  2. Disengage or keep the robot clear of crew/equipment while changing mode.
  3. In Setups -> Target Tracking Setup or the job's Job Type / Target Tracking controls, switch tracking mode to Target Tracking: On.
  4. Ensure focus/target distance is at a sensible value (not infinity).
  5. Then re-engage Carts.

Never switch tracking modes while in Carts with a live rig

Switching between Camera Orbital and Target Tracking while any Cartesian mode is active is the primary trigger for this issue. Always turn Carts off first.

Position focus before enabling Carts

Before entering any Carts mode in Target Tracking:

  1. Drive focus to a working distance (e.g. 100–300 cm).
  2. Confirm the focus readout is realistic.
  3. Only then engage Carts.

Rebuild if it remains intermittent

If the same job continues to exhibit unexpected carts motion:

  1. Save the faulting job for support.
  2. Build a fresh job with the same lens and camera mount values.
  3. Re-enter the key positions rather than copying the suspect job wholesale.
  4. Test without external controllers connected, then reconnect HHB/gamepad devices one at a time.

Keep E-stop accessible

When switching between tracking modes near set or talent:

  • Keep one hand on or near the E-stop at all times
  • Brief all crew that unexpected rig movement can occur during mode switches
  • Switch tracking modes only when the rig is in a safe, clear position

WhatsApp Excerpts

"The Bolt started running in carts after switching from orbital to target tracking. Spacebar did not stop it. E-stop was required. It moved well away from the programmed position." — Multiple operators (paraphrased)

"I was in orbital and switched to target tracking immediately... Using the stop/escape/or space bar didn't stop the movement... The rig was really moving." — Niko (2024-04-27)

"That is the behavior I experienced as well. Had to hit the red e-stop." — Josh T. (2024-04-27)

"Out of carts it stops." — Niko (2024-04-27)

"When switching tracking mode from Camera Orbital to On while in any Carts mode, the camera starts to drift slowly. When you do 'Carts Off' drift stops." — Alexander Kovalevsky (describing the gentler variant of this issue)

YouTube How Motion Control Powers Virtual Production

▶ 01:48 — Discusses motion control rig safety and the importance of knowing where your E-stop is at all times

Revision History

Date Change Editor
2026-05-24 Initial extraction Tom D / Claude Code

Official Documentation

Flair Classic Manual — Ch.13 Target Tracking — p.207

Flair Classic Manual — Ch.12 Job Type — p.199

Flair 7 Manual — Ch.10 Target Tracking — p.171

Flair 7 Manual — Ch.9 Job Storage: Job Type Configuration — p.163