Dimensions
From Valve Developer Community
The numbers below used default configurations and were only tested in HalfLife 2 Single Player.
Contents 
Source Engine Scale Calculations
The Source Engine 'game unit' corresponds to the Grid Unit in Hammer and XSI editors. The Scale used for Source game maps and models is based on the Imperial Foot so Metric measurements do not translate easily. Maps, architecture and prop models use a scale of 1 foot = 16 units.
 Skyboxes (which are 1/16th scale of ordinary maps) use 1 foot = 1 unit.
 Human Character models for Source Engine currently use 1 foot = 12 units.
Texturemaps are applied to Models and Brushwork in the Source Engine and are therefore scaled relative to game units.
 At the default Texturemap scale (0.25) 1 texture pixel = 0.25 x 0.25 units (or 4x4 texels = 1 grid unit). Eg: an (undistorted) 512 x 512 texture covers 128 x 128 game units.
 At the default Lightmap scale (16) 1 lightmap pixel = 16 x 16 units.
Speed is usually given in mapunits per second. To convert this to Miles per Hour, multiply by (15/352).
Map Grid Units: quick reference
Map Grid Imperial Metric 1 = 0.75" = 19.05mm 2 = 1.5" = 38.10mm 4 = 3" = 76.20mm 8 = 6" = 152.40mm 16 = 1' = 304.80mm 32 = 2' = 609.60mm 64 = 4' = 1.22m 128 = 8' = 2.44m (160 = 10' = 3.05m 256 = 16' = 4.88m 512 = 32' = 9.75m Player Collision Hull 32 = 2' 0" width & length 36 = 2' 3" height crouching 72 = 4' 6" height standing Player Eyelevel 28 = 1' 9" height crouching 64 = 4' 0" height standing Architecture 128 = 8' 0" normal corridor height 64 = 4' 0" normal corridor width 108 = 6' 9" normal door height 48 = 3' 6" normal door width
Skyboxes
 1 skybox grid unit = 1 ft
 1 mile = 5,280 ft (1/4 mile = 1,320 ft).
 1 acre = 66 x 660 ft (209 x 208 ft).
 100 yards = 300 ft.
 100 meters = 328 ft.
 1 hectare = 328 x 328 ft.
 2 hectares = 656 x 328 ft (=464 x 464 ft).
 3 hectares = 984 x 328 ft (=568 x 568 ft).
 4 hectares = 656 x 656 ft.
Player Collision Hull
These are the numerical values related to dimensions while mapping. They include the minimum space required for player passage. See also Player Hull.
Ground Obstacle Height
This is the maximum height, in units, an object can be while still allowing the player to walk over it.
 Crouched: 18
 Standing: 18
Overhead Obstacle Height
This is the minimum distance, in units, that can be between the ground and an object while still allowing the player to pass underneath.
 Crouched: 37
 Standing: 73
 Left 4 Dead Crouched: 56
 CounterStrike Source Crouched: 50
 CounterStrike Source Standing: 63
Minimum Path Size
This is the minimum size, in units, that can be between two objects while still allowing the player to pass between them.
 Width: 33 (Between collision surfaces oriented along the x or y axis.)
 Width: 46 (Walls rotated 45 degrees to grid.)
 Width: 65 (Onaxis width between walls skewed to 45 degrees relative to grid.)
 Height: 37
Gradient
This is the maximum slope angle, in degrees from the horizontal, that the player can scale. Anything steeper than this is unclimbable.
 Gradient: 45°
Reach
 Automatic pick up item (ammo/weapon): 25 from center. ie 9 units beyond the Player Collision Hull.
 Max Distance to use switch/doorhandle/etc: 82 units.
Player Viewpoint
Field of View
Change the default Horizontal FOV in HL2 by typing fov xx
in the console, where xx is the number in degrees.
 Player default = 75°
 View Model = 54° (
viewmodel_fov
)  Suit Zoom = 25°
 Crossbow = 20°
 HL2 Jeep = 90° (
r_jeepFOV
)
Eyelevel
This is the Height above the floor on which the player is standing.
 Crouch : 28 units (+ Jump = 49 units)
 Stand/Walk/Run/Sprint : 64 units (+ Jump = 85 units)
 Jump: adds 21 units.
Player Movement Data
These are the numerical values for the various settings related to movement in HalfLife 2.
Speed
 Crouching: 63.33 (2.7 mph)
 Walking: 150 (6.4 mph)
 Running: 190 (8.1 mph)
 Sprinting : 320 (13.6 mph)
 Surface Swim Speed: 152 (6.5 mph)
 Surface Swim Fast Speed: 256 (11.3 mph)
 Surface Swim Slow Speed: 120 (5.1 mph)
 Aux power flashlight: 43 seconds
Sprinting
 Speed: 320 units per second (13.6 mph)
 Max Distance: 2560
 Max Duration: 8 seconds
 Recovery time: 8 seconds
Sprinting with Flashlight
 Max Distance: 1920
 Max Duration with flashlight: 6 seconds
Jumping
Vertical (To High Point)
This is the maximum height, in units, an object can be while still allowing the player to jump on top of it.
HL2 Step Height +Jump +JumpCrouch Crouching: 18 21 21 Standing: 18 20 56 Walking: 18 20 56 Running: 18 20 56 Sprinting: 18 20 56
CS:S Step Height +Jump +JumpC +CJumpC Crouching: 18 56   Standing: 18 52 61 65 Walking: 18 52 61 65 Running: 18 52 61 65 Sprinting: 18 52 61 65
Horizontal (To Equal Height)
This is the maximum distance, in units, that can be between two objects of the same height, while still allowing the player to jump from one object to the other.
 Stationary: 84
 Stationary crouched: 40
 Crouched: 99 now 62
 Walking: N/A will not jump while walking
 Running: 176
 Running crouchjump: 225
 Sprinting crouchjump: 272
High Point to Low Point
This is the distance while falling to a lower point.
 Taking no damage: Drop 185 : Span 415.
 Taking 98 damage: Drop 692 : Span 540.
Jumping Using the Gravity Gun
Firing a single shot straight down at a prop_physics model (props_debris/metal_panel01a.mdl) = 350 units
Jumping, pulling, then firing, then pulling, and firing again = 400+ units
Falling Damage
This is the damage taken when falling straight down.
 Terminal velocity: 3500 (150mph)


Swimming Underwater
 Speed: 152 (6.5 mph)
 Sinking Speed (no keys): 48 (2.0 mph)
 Max Distance (no damage): 2523
 Max Distance (still alive): 3848
 Max Depth & return to surface (no damage): 1325
 Max Depth & return to surface (10 hp remaining): 2000
Swimming Underwater with Flashlight
 Max Distance (no damage): 2170
 Max Distance (still alive): 3535
 Max Depth & return to surface (no damage): 1190
 Max Depth & return to surface (still alive): 1850
Vehicles
Buggy
 Buggy speed normal: 821.3 (35 mph)
 Buggy reverse: 469.3 (20 mph)
 Buggy speed turbo: 1173.3 (50 mph)
 Climb angles: ramp = 3900 l x 1670 h 564 l x 504 h
 Climb angle from stopped: 63 deg
 Climb angle no turbo: 66 deg
 Climb angle turbo: 50 deg long 42 deg short
 Jump distance normal: 216
 Jump distance turbo: 860
 Overhead obstacle height: 90
 Minimum path width: 118
 Stall depth: 40 sputters at 37
Airboat
 Airboat forward: 797.9 (34 mph)
 Airboat reverse: 797.9 (34 mph)
 Climb angle no full throttle momentum: 55
 Jump distance same height: 856
 Overhead obstacle height: 86
 Minimum path width: 86