In Flight Simulator scenery, designs are done in 3-D, 16-bit integer design space. For example, a line can run from 1000, 2345, -2345 (x,y,z coordinate) to 1345, 832, 25. The range of numbers is limited to +-32767. What the design units represent in physical size depends on scale factor.
Scale factor is specified as a whole integer number. This number represents a fixed ratio of design units to units of physical length. The following table includes the scale factor numbers and what the numbers represent.
Note: In Flight Simulator, some scale commands use whole scale numbers (0–24), but the other scale commands have fractional scale factor capability. These commands have a 32-bit scale factor argument that is filled with 65536/value units/M. For example; the value 13768 represents 65536/13768 or 4.76 meters per unit. Units that fall between the values shown in the following table are possible using fractional values.
| BGL Scale | BGL scale name (from bglmac.asm) | BGL map_scale command | Meters/design units | Units/meter | Units * 65536/M (used in fractional scale commands |
| 6 | S_6 | NA | .9765mm | 1024 | 67108864 |
| 7 | S_7 | NA | 1.953mm | 512 | 33554432 |
| 8 | S_8 | NA | 3.906mm | 256 | 16777216 |
| 9 | S_9 | NA | 7.812mm | 128 | 8388608 |
| 10 | S_10 | NA | 15.62mm | 64 | 4194304 |
| 11 | S_11 | NA | 31.25mm | 32 | 2097152 |
| 12 | S_12 | NA | 62.5mm | 16 | 1048576 |
| 13 | S_13 | NA | 125mm | 8 | 524288 |
| 14 | S_14 | NA | 250mm | 4 | 262144 |
| 15 | S_15 | NA | 500mm | 2 | 131072 |
| 16 | S_16 | 16 | 1m | 1 | 65536 |
| 17 | S_17 | 17 | 2m | .5000 | 32768 |
| 18 | S_18 | 18 | 4m | .2500 | 16384 |
| 19 | S_19 | 19 | 8m | .1250 | 8192 |
| 20 | S_20 | 20 | 16m | .0625 | 4096 |
| 21 | S_21 | 21 | 32m | .0312 | 2048 |
| 22 | S_22 | 22 | 64m | .0195 | 1024 |
| 23 | S_23 | 23 | 128m | .0097 | 512 |
| 24 | S_24 | 24 | 256m | .0048 | 256 |
| 25 | NA | 25 | 512m | NA | 128 |
| 26 | NA | 26 | 1024m | NA | 64 |
| 27 | NA | 27 | 2048m | NA | 32 |
| 28 | NA | 28 | 4096m | NA | 16 |
| 29 | NA | 29 | 8192m | NA | 8 |
| 30 | NA | 30 | 16384m | NA | 4 |
| 31 | NA | 31 | 32768m | NA | 2 |