GURPSよろず

OPTIONAL RULE: DENSITY OF VEGETATION
When anyonemoves through an area thick with plants, there are a number of effects. The GM can designate a particular area as Sparse, Normal, Dense, or Impenetrable. The effects of each density described below are for a normal human on foot.

Sparse: Long-distance, straight-line movement is possible only at this density level. Equivalent to Average ground travel terrain (p. B351). If you are using the Environmental limitation (GURPS Powers, p. 110), this level is -20% (outdoors/ wilderness).

Normal: While running, roll every 100 yards against the better of DX or DX-based Running to avoid an ordinary mishap (e.g., trip and fall down). For purposes of clearing or burning, each hex has 25 HP. Equivalent to Bad ground travel terrain. If you are using the Environmental limitation, this level is -30% (ordinary vegetation).

Dense: All ranged attacks modified by -2 due to automatic cover for targets. While walking, roll against DX every 50 yards, suffering a minor mishap only on a critical failure. If you are running, use the same rule for Normal density, above, and penalize the roll by -2. Additionally, certain characteristics are modified: +3 to Stealth, +2 to Camouflage, -2 to Move, and -2 to Vision rolls. Each hex has 40 HP. Equivalent of Very Bad ground travel terrain. If you are using the Environmental limitation, this level is -40% (dense vegetation).

Impenetrable: A SM 0 or larger creature cannot pass through the undergrowth! It gives -6 to Vision rolls. Creatures small enough to enter (see below), get +4 to Stealth and Camouflage.
Each hex has 65 HP. Furthermore, the vegetation acts as a barrier, and it may function as cover from ranged attacks.

Creatures at SM -1 or SM -2 pass through vegetation at one step lower; e.g., a halfling moves through Impenetrable as if it was Dense. At SM -3 or smaller, move down two steps.
This applies only to movement through the hex, not skill modifiers or cover. Creatures of SM +1 or greater treat Dense as Impenetrable and Normal as Dense.

Unless otherwise noted, assume jungle, swampland, and woodlands are Normal and plains are Sparse. In a cinematic campaign, jungle is often Dense. These rules are used with the following spells: Breakfall Plants (p. 13), Fast Plant Growth (pp. 12-13), Forest Defense (p. 13), Razor Grass (pp. 16-17), and Run Across Treetops (pp. 17-18).