Moving-head calibration

To aim, DreamShow computes a moving head's pan and tilt from its position in the venue, its rigging and the pan / tilt ranges of its definition: this is the geometric model. It is good, but a head rigged slightly crooked, a bar not quite at the measured height or an approximate definition will make it aim off target. The 4-point calibration corrects this: for each corner of the stage, you show DreamShow which pan and tilt values actually send the beam there. Afterwards, any point of the stage is aimed at by interpolation between these measurements, as accurately as possible.

To open it: select one moving head only, then click the Calibrate… button in the toolbar of the Venue panel. If no moving head is selected, the information line at the top of the main screen shows “Calibrate: select a moving head”; if there are several, “Calibrate: one head at a time”. The head must have a position in the venue and a definition with a pan.

When to calibrate

When aiming must be precise on the stage: convergences, follow spot on a tablet, tight zones.
When a moving head visibly aims off target although its position is right.
After the moving heads have been re-rigged.

Calibration is done on the real equipment: the DMX output must work (LIVE on) and you must be able to see the stage.

The six points

The “Calibration — (name of the head)” window stays above the other windows and does not block the main screen. It offers six points:

Stage-right corner – upstage
Stage-left corner – upstage
Stage-right corner – downstage
Stage-left corner – downstage
Back wall – left (top) (optional)
Back wall – right (top) (optional)

The four corners are those of the stage declared in the venue (width, offset, depth), on top of the floor. The two back-wall points are halfway up between the stage and the ceiling, directly above the stage-right and stage-left edges of the stage. The four corners are enough; the two wall points extend aiming onto the back wall.

For each point, the line shows on the right the captured value (“pan 48.2 tilt 31.5”, as a percentage of the range) in green, or “—” if there is nothing, and three buttons:

Model: places the head on this point according to the geometric model. The real head moves there: this is the starting point, and only the difference remains to be corrected.
Capture: keeps the head's current pan and tilt for this point. If the head has no pan / tilt set yet: “No current pan/tilt value for this head: set it first (sliders or “Model”).”
×: forgets this point.

Under the list, a help line tells you where you stand: “N/4 stage corners captured — all four are needed to save.”, then “The four corners are there: you can save” (“(with the back-wall extension).” if the two wall points are captured too).

Buttons at the bottom:

Pre-fill everything (model): fills the six points from the geometric model (the head's position, pan / tilt ranges, mounting), without moving the head. Saved as it is, it is a “default” calibration.
Save the calibration: saves the calibration in the venue (immediately, in its file) and closes the window. All four corners are needed (“Capture the four stage corners first.”). The wall points are kept only if both are captured. The log notes “(name): calibration saved” (“(with the back wall)” where applicable).
Delete (geometric model): removes the head's calibration; aiming goes back to the geometric model. The log notes “calibration removed (geometric model)”.
Close: closes without saving.

If the head already has a calibration, its points are displayed when the window opens.

How the head is driven during calibration

Model and the Pan and Tilt sliders of the Scene settings panel write into the final state of the selected scene (or into the effect or keyframe being edited), like any setting. The head also receives, if it does not have them, intensity at 100 %, the shutter open and the maximum pan / tilt speed. If LIVE is on and this scene is the one playing, the real head moves.

So calibrate on a working scene (or a scene you can clean up afterwards), then remove the head from the final state if it must not appear there (Remove from the final state button of the Scene settings panel).

Step by step: calibrating a moving head

Check the head's position and the stage dimensions in Venue > Fixtures, addresses, positions….
Turn LIVE on, select a working scene in the Scenes panel. Black out the other fixtures to see the beam clearly.
Select the head alone, then Calibrate….
On the 1. Stage-right corner – upstage line, click Model: the head moves near the corner.
Correct with the Pan and Tilt sliders until the centre of the beam touches the corner exactly (a mark on the floor helps).
Click Capture: the value appears in green.
Repeat for the other three corners.
Optional: do the same for the two back-wall points.
Save the calibration.
Check with Aim: click at different places on the stage, the beam should land under the mouse.
Do the same for each moving head.

What calibration is used for afterwards

A calibrated moving head uses its calibration, instead of the geometric model, for:

Aim at a point of the stage (see Aiming and covering a zone with moving heads);
follow spot on a tablet when the finger is on the floor (see Follow spot on a tablet);
the aims written automatically by the first-show assistant;
the simulation: the beam's impact point drawn on the stage follows the calibration.

The Zone tool uses it in the same way, for any point of the zone located on the stage.

Outside the stage (house, side walls), and above it if the wall points are not captured, the geometric model does the aiming.

Saving and reloading calibrations

Calibrations are part of the venue: they follow Duplicate the venue… and the project export. To save them separately or to take them over from a ppshow installation: Venue > Export the calibrations… and Venue > Import the calibrations (lyrescal.ini)… (see Switching, renaming, duplicating a venue).

Good to know

A calibration is valid for one rigging position: if the head is moved or re-rigged, recalibrate it.
Duplicating a fixture in the venue does not copy its calibration.
Changing a fixture's identifier does not make it lose its calibration (it is saved with the fixture), but a calibration file exported earlier will no longer find it under its old identifier.
If the Fixtures, addresses, positions… window is open during calibration, saving the venue from it afterwards would erase the new calibration: close it before calibrating.
The calibration window stays in the foreground: move it to see the Pan and Tilt sliders.