The term “prefire” means the time from firing system ignition to the effect time that is synchronized to the music. For aerial shells, the prefire is usually associated with the lift time. In fact, the association is so close that people often use the terms interchangeably. VDL supports this common usage with the special rules,
Prefire < 0.5 defines delay before simulation;
Prefire >= 0.5 defines aerial shell lift time
In other words, if the prefire is a small fraction of a second, then it refers to the latency introduced by the firing system or the time it takes for the effect to get started. If the prefire is in the range that it could be a lift time, then that’s what it is. These rules work almost all the time, so you usually don’t need to give much thought to it.
The rules even work for combination effects like RED PEONY w/ BLUE MINE, or BLUE MINE w/ RED BOMBETTES. If you want to synchronize the launch of the mine to the music, specify a small prefire < 0.5. If you want to synchronize the break of the shell to the music, specify a larger prefire, being the lift time of the shell.
The prefire can be specified in the effect window table in the “Prefire” column explicitly, or it can be included in the VDL using the term PFT (see VDL timing adjustment terms). If the prefire is specified in both places, the value in the window table prevails.
LFT and DLY
In circumstances for which the prefire rules are insufficient, the LFT and DLY terms in VDL specify the lift time and delay before simulation, taking precedence over whatever the default lift time would be or whatever the prefire implies. Consider the case of a bombette roman candle with a 1.0 second fuse prior to the first launch, and then 2.0 seconds between the shots, and finally 3.0 seconds lift time in each of the bombettes. You can define this effect in VDL as,
50mm 21.0s 4.0 PFT 10 Shot RC 1.0 DLY Pink Peony w/ Green Mine 3.0 LFT
Breaking this phrase apart, you can see the 3.0 LFT time at the end, defining the lift time. The 1.0 DLY is the delay before simulation, representing the delay before the first launch as the visco fuse works its way down into the roman candle tube to the first shell. The 4.0 PFT aligns the prefire with the first break, which occurs at 1.0 seconds + 3.0 seconds = 4.0 seconds after the firing system ignition. The overall duration of 21 seconds measures first launch to last break (see Cake and candle duration), so that’s 18 seconds between the first launch and the last launch, accounting for the 3 second lift time to the last break. There are 9 gaps between 10 shots, so 18/9 = 2 seconds between shots.
Editable fuse delay
If you need to represent a long fuse in front of the device, like a Pyro-Clock fuse or a Visco fuse on a cake, then the “Delay Default” field in Finale 3D may be better suited to your purpose than “Prefire“.
The Delay Default field in Finale 3D is an external delay between the firing system ignition and the ignition of the effect. The column is normally hidden in the effects window and the script, so click the blue gear menu in the upper right of those windows to unhide it. In the effects window, the column is called “Delay Default” whereas in the script window it is called “Delay”. The reason it is called “Delay Default” in the effects view is that when you insert an effect the “Delay Default” is copied by value into the script’s “Delay” field. Once it is copied into the script, you can edit the Delay in the script on a row-by-row basis, as you might need to do if you were adjusting the length of the delay fuses on an item by item basis in the physical world. Thus the “Delay” in the script can be different for different occurrences of the same effect.,
The prefire values in your effects list can come from a variety of sources. If you measure your effects’ prefire times yourself in the real world using photography or a stopwatch — from firing system ignition to break — then the times will incorporate any latency from your firing system into the prefire times. Thus,
Measured prefire = delay before launch + lift delay
It works fine to use these prefire times directly in Finale 3D. Here’s why: Finale 3D will interpret them for shells as just the lift delay, following the rules described above. Thus the simulated launches will leave a little early and the breaks will linger compensatingly long to make them hit exactly at the prefire. But this slight inaccuracy is okay because small changes to the shape of the trajectory are virtually imperceptible, and if you are entering prefires >= 0.5 to synchronize the breaks to the music, then you probably don’t care if the launch begins a little early. If the shell includes a bouquet of mine stars as part of the effect, then you probably would be synchronizing the music to the mine launch with a prefire < 0.5 and wouldn’t care about a slight inaccuracy in the shell breaks. If you have any objection to the approximations, you can fix them with LFT and DLY.
Using lift times from suppliers as prefire
As an alternative to measuring your own prefire times, you may use the prefires or lift delays provided by your suppliers. These times obviously wouldn’t take into consideration any delays introduced by your firing system. Thus,
Prefire from supplier = lift delay
If the delays introduced by your firing system are enough to pay attention to, you have two choices. You can add them to the prefire times from the supplier, modifying the effects lists, or you can set the “Firing system export offset” in the “Show > Show settings…” dialog in Finale 3D. To compensate for a positive delay enter a negative number as the export offset, e.g., -0.1 if your firing system adds a latency of a tenth of a second.
An advantage to the using the export offset for firing system latency instead of folding firing system latency into the prefires is that your prefire values are then not firing system dependent. You could re-purpose an existing show from one firing system to another by simply changing the export offset.