And I will post my prototypes, so others can learn.

1st decision - have sword as separate entity
-----------------------------------------------------
A) I know Quake knight monster has simplistic traceline test whether he hist enemy. It is simple and I guess it works.
B) I want to make sword as separate entity not as usual model glued to character like weaponst and move it at will (it can then have more physics which might be nice).
2nd decision - movement of a sword
----------------------------------------------
I thought about copying something from Dark Messiah (Arx Fatalis had almost the same movements), Thief and Die By The Sword. I want to try to make trajectory and then test whether sword hits something. I will see how will work on some sparing partners (entities) ...
3rd movement description
-------------------------------
I want to make it easy for me to write it. And possibly for my girlfriend.

A) cartesian (distance, distance, distance) ........ no thanks
B) cylindrical (angle, distance, distance) ........ it seems reasonably readable for human
C) spehrical (angle, angle, distance) ......... maybe
So I am going to stick with B or C.
I know I could make it in some 3D studio. Hmm ... maybe I will.

Questions
----------------------------
Is it correct to call one cartesian coordinate radius instead of distance?
Does anyone have experience with making swordplay game?
Did someone make some swordplay game and posted insights?
Is there any paper about game swordplays?