General mapping information


This page contains general information, limits and sizes that are useful to know when mapping for ETJump. All measurements assume pmove_fixed 1 and com_maxfps 125 unless stated otherwise.

Player sizes

Values are rounded to integers to match grid in Radiant. Actual values for clearances can be lower, as long as they are still bigger than the bbox.




Style Max speed (units/s)
Sprint 352
Run 256
Walk 129
Walk + sprint 177
Crouch 80
Prone 67
Groundstrafe 452
Wallstrafe 442


If water level is < half of your height (stance dependant), you are still walking normally but your speed is clamped to 267 units/s.

Following values assume axial yaw. Non-axial yaw can provide higher speeds.


Stepup happens when you are moving against a vertical wall and are within 18 units (vertically) of the top surface. Stepup doesn't happen if the wall is angled towards you from the bottom, unless the top surface is a seperate brush.

When stepup can happen, jumping direction from left to right.

Jump height

FPS Height (excl. stepup) Height (incl. stepup)
< 125 45 63
125/333 46 64
250 43 61
500 54 72
1000 36 54

If the top of the brush you are trying to jump onto is angled, it's possible to jump onto higher surfaces than these. The angle of the top matters; maximum values (with pmove_fixed 1 and com_maxfps 125) are 76 units for a standard jump, and 87 units for a backwards prone jump, when the top is at 45 degree angle.

Jump timing

Note: due to pmove_msec 8, all jump timings have +/- 8ms margin of error. The times here represent the elapsed time between jumping and landing.

Fall damage

Fall damage is calculated from falling speed, not height. These measurements assume flat ground to flat ground with standard gravity.


Fall damage Max height
0 hp 258 units
5 hp 320 units
7 hp 386 units
12 hp 446 units
25 hp 513 units
Death >514 units


Fall damage Max height
0 hp 209 units
5 hp 271 units
7 hp 337 units
12 hp 398 units
25 hp 464 units
Death >464 units

When you take fall damage from a fall/jump, the game applies knockback event on you (slick physics). This lasts for 1000ms for every fall damage event, except for 12hp falls, where it only lasts for 250ms.

Map limits

Compiler limits

Engine limits

Common errors and warnings

Common shaders

This list contains common shaders that are useful for ETJump mapping. This is not a comprenesive list; it only includes stuff thats relevant and actually works. Clip shaders for example have variations with different surface sounds, but they are self-explanatory and are not listed here.

Stock ET

ANTIPORTAL - Combines areaportal and hint into a single shader. Difficult concept to understand (don't understand it myself fully either). Use in conjunction with skip. Some talk about their usage here and here.
AREAPORTAL - Blocks VIS by culling everything behind it. Must be placed inside door entities to work. Use in conjunction with skip.
CAULK - Solid, invisible surface. Generally any surface not visible to player should be caulk.
CLIP - Invisible surface that blocks player movement but lets everything else through. Used for smoothing out movement and to block non-playable areas.
CLIPMISSILE - Invisible surface that blocks players, projectiles and entities, but lets bullets through.
CLIPWEAP - Invisible surface that blocks everything.
CUSHION - Solid surface that disables fall damage.
HINT - Structural surface that creates a portal to force a split in PVS. Use in conjunction with skip.
SKIP - Structural surface that doesn't create a split in PVS. When placing hint brushes, use this on every surface where you don't want a portal to be created.
HINTSKIP - Same as skip, but filters with hint in Radiant.
LADDER - Surface that players can grab onto and climb. Note that ladders don't work if vertical angle is under 45 degrees.
LIGHTGRID - Defines the area included in lightgrid calculation. Lightgrid has a block limit; this can be used to exclude unnecessary areas from it and shrink each block.
NODRAW - Invisible, nonsolid surface. Explicitly marked as a detail brush.
NODRAWNONSOLID - Same as nodraw, but doesn't explicitly make the brush detail.
NODRAWWATER - Applies water properties to a brush. Use on non-visible faces of water brushes.
NODROP - Entities inside this brush disappear when they touch the ground.
ORIGIN - Used to define origin point for various brush entities. The center of the brush will become the origin of the entity.
SLICK - Solid, slippery surface.
TRIGGER - Used for trigger entities.



If you don't see these shaders in Radiant, make sure you have the latest ETJump mapping assets, available here. nosave, overbounce and portalsurface shader functionality can be reversed with worldspawn keys.

NODRAWSLAG - Same as nodrawwater, except has slightly lower acceleration scale (0.3 vs 0.5). This is technically a stock shader, but it's not shipped with Radiant.
NOSAVE - Players cannot save inside this brush.
OVERBOUNCE - Players cannot OB on this surface.
PORTALSURFACE - Players cannot shoot portals on this surface.
SLICKCUSHION - Surface that both disables fall damage and is slippery.