The VDL language supports whatever degree of detail you want to include in your cake descriptions. Descriptions can be generic, like,
49 Shot Red Pearl Z-Shape Cake
or more specific, like,
49 Shot 5s (a) Red Pearl + (b) Blue Pearl Cake Z-Shape, 7 Rows, Row 1,3,5 (aaaaaaa), Row 2,4,6 (bbbbbbb), Row 7 (1.2/abababa/FNT)
If you want to specify the firing pattern for each row of a cake, then your VDL cake description will look more like the specific example, above, and it will contain row descriptions for every row in the cake. In this example, rows 1, 3, and 5 have a simple row description, specifying seven shots of effect (a), the Red Pearl. Rows 2, 4, and 6 are similar for effect (b). But row 7 includes more specifications. The three letter “FNT” at the end of the row 7 specifications is the “Firing Pattern Keyword”, which specifies the angles of the shots in the row, and whether there are delays between the shots, and which end of the row is ignited to shoot first.
In this specific example, the term “Z-Shape” in the body of the cake description defines the default firing pattern for the cake as a whole. Z-Shape declares the rows will fan shots from left to right and back, alternating with each row. Since the firing descriptions for rows 1-6 do not specify any changes to that default firing pattern, the Z-Shape firing patterns will apply to rows 1-6. But row 7 does specify a change, with the firing pattern keyword, FNT. The term “FNT” stands for Fan-together. This last row of the cake is thus an all-at-once fan of seven shots of alternating colors based on the letters (a) and (b).
If a cake description doesn’t include any firing patterns in the body of the description, then the default firing pattern for every row will be the Up-Sequence firing pattern, abbreviated “STR“, which means all the tubes are aiming straight up (the “ST” for straight up) and they are fired in left to right order in the row (the “R” for left to right order). A similar firing pattern is Up-Reverse, abbreviated “STL“, which is the same except fired in the reverse order, right to left. The left-to-right or right-to-left order distinction matters when the row contains multiple kinds of effects (the a’s and b’s, for example) in a non-symmetric pattern.
A third straight up example is Up-Together (“STT“) which is all tubes firing at the same time. Two other common fan firing patterns are “FNR“, and “FNL“, for Fan-Right, and Fan-Left. The full list of firing patterns is defined in Table 1.
Table 1 – Firing pattern keywords
|Firing pattern keywords|
|Term||Pattern||Timing||Description||Ignited from which end||Also called|
|ALR||\\\||Sequential||Left-Sequence||Left||AGW (and also see Table 2 of Cake descriptions)|
|FNR||\|/||Sequential||Fan-Right||Left||FNW (and also see Table 2 of Cake descriptions)|
|FNL||\|/||Sequential||Fan-Left||Right||(see Table 2 of Cake descriptions)|
|FNT||\|/||All-At-Once||Fan||Undefined||ATF (and also see Table 2 of Cake descriptions)|
|BLR||\|||Sequential||Stand-Right||Left||BKW (and also see Table 2 of Cake descriptions)|
|BLL||\|||Sequential||Fall-Left||Right||(see Table 2 of Cake descriptions)|
|BLT||\|||All-At-Once||Left-Bookend||Undefined||BKT (and also see Table 2 of Cake descriptions)|
|BRR|||/||Sequential||Fall-Right||Left||(see Table 2 of Cake descriptions)|
|BRL|||/||Sequential||Stand-left||Right||(see Table 2 of Cake descriptions)|
|CTO||\|/||Sequential||Center-Out||Center||CRN (and also see Table 2 of Cake descriptions)|
|OTC||\|/||Sequential||Outside-In||Left And Right||(see Table 2 of Cake descriptions)|
|TRI||\|/||All-At-Once||W-Shape *||Undefined||(see Table 2 of Cake descriptions)|
|TRS||\|/||Sequence-Of-Ws||W-Shape *||Right End Of Left Tubes, And Left End Of Center Tubes, And Left End Of Right Tubes||(see Table 2 of Cake descriptions)|
|VSS||\/||Sequence-Of-Pairs||V-Shape||Center||(see Table 2 of Cake descriptions)|
* TRX is the same as TRI except when the number of tubes in a row is not divisible by 3: TRI adds the remainder as straight tubes; TRX adds the remainder as angle tubes. For example, TRI of 11 tube rows has the pattern 3-5-3, whereas TRX has the pattern 4-3-4. TRS defines a sequence N / 3 Ws, for N = the number of tubes in the row. If N / 3 has remainder 1, then the extra tube is the left-most center tube; and it is shot along with the tube immediately to its right and the right-most left tube and the left-most right tube, i.e., the first W having 4 tubes shooting simultaneously instead of three. If N / 3 has remainder 2, then the extra tubes are the right-most left tube, and the left-most right tube; and the extra tubes are shot with their immediate neighbors and the left-most center tube, i.e., the first W having 5 tubes shooting simultaneously.