| SIZ Mod | ||||
| Roll | Gravity Range | Ht | Wt | Notes |
| 1 | < .2 G | +3 | 90% | Native of a planetoid, orbital city or starbase and has adapted to low and null gravity conditions. Low gravity favours development of a tall but slight frame. Gravity fields in the 1 G range or higher will prove to be quite uncopmfortable. Atmosphere type 1 default. |
| 2-3 | .25 to .4 G | +3 | 90% | Adapted to low gravity conditions. Gravity fields in the 1 G range or higher will be rather uncomfortable. Atmosphere type 1 or 2 default. |
| 4-9 | .5 to .8 G | +2 | 95% | Somewhat adapted to low gravity conditions. |
| 10-16 | .9 to 1.1 G | Native of planet with standard "Terran" gravity. | ||
| 17-18 | 1.2 to 1.4 G | -2 | 110% | Adapted to high gravity conditions. High gravity encourages heavier bone structure and muscle development. |
| 19 | 1.5 to 1.8 G | -3 | 115% | Adapted to very high gravity conditions. |
| 20 | 1.9 to 2.5 G | -4 | 120% | Is a superbly adapted heavy planet dweller. |
