Triggers / Bloop Don't Fire During Back Runs — Negative Frame Values¶
Summary¶
Triggers (bloop light, camera record start/stop) programmed at negative frame values do not fire when the robot runs in the back direction. This affects both the standard trigger system and camera record mode. The workaround is to restructure the move so that trigger frames land at positive (or zero) frame values.
Symptoms¶
- Bloop or camera record trigger programmed before frame 0 (e.g. frame -10) does not fire during back run
- Forward run: triggers fire correctly; back run: triggers silent
- In camera record mode: triggers at negative frame values are not sent
- Oscar Molano confirmed (November 2022): "Camera record doesn't fire triggers below frame 0 in my tests"
Technical Background¶
Flair's trigger system evaluates trigger frame values as the playhead moves through the timeline. During a back run, the playhead travels in the negative direction. Trigger events at negative frame numbers are not evaluated during this pass — Flair only fires triggers at positive frame positions during normal forward or back runs.
This is a known Flair behaviour, not a wiring or configuration fault.
Workaround Options¶
Option 1 — Add a Hold at the Start and Use Positive Frame Values (Preferred)¶
In the move table / timeline editor, add a hold (static position, zero velocity) at the very beginning of the move for the required duration. Then open the trigger / camera record controls and shift all trigger frame values to positive numbers that land within that hold period.
Example: bloop needed 10 frames before the move starts 1. Add a hold of 20 frames at the beginning of the move in the move editor. 2. In the trigger / camera record controls, move the bloop trigger from frame -10 to frame 10 (still 10 frames before motion begins). 3. All triggers are now at positive frame values and will fire on both forward and back runs
Recommended approach
This is the cleanest fix. It preserves the trigger timing relative to the move and is fully reversible.
Option 2 — Flip the Move Direction¶
Flip the entire move so that what was the back direction becomes the forward direction.
Motion curves recalculate when flipping
When a move is flipped in Flair, the motion curves (acceleration, deceleration profiles) are recalculated. This can introduce a slight variation in the motion compared to the original. On critical VFX passes where exact repeatability matters, test thoroughly before committing to this approach.
Option 3 — Camera Record Mode: Move All Triggers to Frame 0 with a Pre-Frame Hold¶
For camera record mode specifically (where triggers below frame 0 are suppressed):
- In the camera record / trigger controls, move all camera record triggers to frame 0.
- In the move editor, add a hold at the start of the move for the desired number of frames before the real action begins.
- The trigger at frame 0 will fire, and the hold provides the pre-roll buffer
Oscar Molano confirmed this workaround in November 2022.
Summary Table¶
| Scenario | Fix |
|---|---|
| Bloop/trigger at negative frames, any run mode | Add hold at start, shift trigger to positive frame |
| Flipping move acceptable | Flip move direction (verify curve accuracy) |
| Camera record triggers below frame 0 | Move triggers to frame 0, add hold of required duration before frame 0 |
References¶
- Niko, Tom D — community discussion May 2022
- Oscar Molano — camera record confirmation November 2022
- Flair Operator Manual — Triggers / Camera Record Setup (Flair Classic — Ch.19 Inputs, Outputs & DMX: Triggers On/Off — p.286 · Flair 7 — Ch.16 Inputs, Outputs and DMX: Triggers On/Off — p.236)
Official Documentation¶
WhatsApp Excerpts¶
- 2022-05-19 07:14 - ~ Niko: Hi guys, working with triggers activated before the movement starts (negative frame values), I always noticed that shooting in back run sometimes the triggers don't work or work less time than expected The only 2 ways to make it work is using the flip move option and change the "on frame" values to the new end (previous st as rating point) or adding a hold at the begining with enough frames before the starting, and also changing the on frame values. Both options need changing the on frame...
- 2022-05-19 08:11 - Tom D: I tried “flipping” a move to overcome this issue of the bloop light not turning on at a negative value when running a move backwards (we wanted to shoot a reverse plate to overlay the regular plate we just shot). However in this case the flipped move ran slightly differently as the motion curves were calculated differently when the move was flipped (luckily I was checking shots overlaid correctly as we went). So has to go back to running the original move backwards, but go without the bloop...
- 2022-05-19 11:11 - ~ Peter Constan-Tatos: Niko yes agree the hold way to avoid negative triggers is the best solution. Tom has pointed out an important risk in flipping that may arise. I wonder if flipping a spline or beziers move both have this possible problem?