A basic CLSN tutorial for all characters by K.O.D (updated on October
04, 2009)
CLSN2 : Collision box (Blue)
CLSN1 : Hit box (Red)
Keep in mind all these :
1. If the character is an existing game character (King of Fighters,
Akatsuki Blitzkampf, etc.) with a CLSN viewer, take the CLSN data
directly from it which is much simpler than explanation (disregard this
tutorial)
2. Basic rule in all good fighting games : 2 CLSN2 boxes on each
animation (at maximum 4 boxes if the sprite is huge, etc.)
3. Basic rule in all good fighting games : 1 CLSN1 box on each
animation (maximum 2 boxes, but it can be
increased to 4 if the animation is a slanted projectile,etc.)
4. Position your boxes a bit out of torso range but within the arm's
range.
5. Always use the same CLSN boxes in the standing animation, do not
change the clsn boxes in any frame of the standing animation (unless
it's a special character which has a complicated stand animation)
6. Use CLSN Default for a CLSN1/CLSN2 box which is the same in all
frames.
7. Do not make the CLSN boxes move unnecessarily in the animation just
for a single limb or head movement,etc.
Note : Even though the character I'm using as an example for this
tutorial is a King of Fighters character, I will change his CLSN boxes
just for the
sake of demonstration.
An example of good standing CLSN2 boxes (clean and practical) :

An example of bad standing CLSN2 boxes (too many unnecessary details
which do not have any effect in gameplay and causes lag on slow PC's) :

Moves which evade High or Low attacks do not have any special property
set for them, instead, the CLSN2 boxes of the move are positioned so
that the opponents hitbox does not hit the player.
This move has Kyo ducking (crouching) before attacking the opponent,
the effect is by the CLSN2 position :

This move has Kyo hopping before attacking the opponent, the effect is
by the CLSN2 position :

Moving onto CLSN1 boxes, there is a thing known as "infinite
priority" which is caused by not overlapping a CLSN1 box with a CLSN2
box which in turn makes the attacker "cheap" by
allowing him to attack without getting hit back.
Remember that Infinite Priority is NOT applicable to some fighting
games which have clever CLSN positioning to further enhance the
"realism" of the gameplay (KoF, Fatal Fury, Melty Blood, etc.) so do
not apply the infinite priority rule to games which do not follow it as
they are meant for their own gameplay style.
Also, swords or any other weapons do not need to have a CLSN2
overlapping the CLSN1 boxes on them, CLSN1 boxes must be within in the
range of the hand/sword/etc. and not
covering much more (however, sword "slashes" can have a wider CLSN1 box
to give accuracy to the slash)
An example of good attack CLSN1 boxes (within range and practical)

An example of good jumping attack CLSN1 boxes (within range, practical
and does not need multiple boxes)

An example of bad attack CLSN1 boxes (has infinite priority,
unrealistic and time consuming)

An example of bad jumping attack CLSN1 boxes (has infinite priority,
unrealistic and time consuming)

Same rules apply for projectiles, keep them within range and keep them
clean.
Projectiles need to have a CLSN2 box covering the CLSN1 box (even in
KoF characters) for getting hit by other projectiles/blocking other
projectiles depending on what type of projectile you are coding.
