How does Crouch jump actually work?

I'm wondering, in all valve games, you can "crouch jump". The action of crouching just before a jump makes you somehow jump higher.

I get that it's kinda more realistic, but was it an intended (programmed) thing, or is it a wonky hitbox when crouching that permits that effect?

Also, side question: How much more (in % if we count the base jump as reference) do you jump with a crouch jump?

source-engine

Best Answer

There are two types of jumping that combine the actions jump and crouch:

Crouch jump: Crouch jumping is available in all GoldSrc and Source (2) games that allow jumping in general. Some mods may have chosen to disable it, but it’s the usual movement model of the engines. Other first person shooters have similar mechanics. The sequence is as simple as jump first then crouch while in air. It can be used to jump over or climb on higher obstacles. Various games (and probably the engines themselves) had multiple bugs which could be exploited by combinations of crouch jumping as a way of cheating in multiplayer games, for example the infamous Bunny Hopping in the original Counter-Strike.
Long jump: This is only available in the original Half-Life (and some mods and maybe Blueshift and Opposing Force). It requires that you are equipped with the HEV suite’s Long Jump Module and is essential for getting through Xen. It is a quick sequence of crouching first and, while still crouched, jump. It will result in a boost by the Long Jump Module and a really long jump (horizontally). This is a bit tricky to master – that’s why you’re teached how to use it in Half-Life’s Hazard Course.

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