Written by Olivier Saraja (olivier_at_linuxgraphic.org)
English version
The Cylindrical Light behaves very much like the Spot Light and all parameters also behave exactly the same. The Cylindrical Light main application is the laser beam, if you are interested in ;o) but in most cases you shouldn't have to specify such a light type.
As its name suggests, the Shadowless Light produces no shadow projection from an object to another: each object is rendered as if it was the only object of the scene. It cast no shadow and receives no shadow except its own.