EXACT exact knife cut?

The “Knife (exact)” tool is a wretched misnomer. There’s nothing exact about eyeballing the positions of mouse clicks.

What I am trying to do is embarassingly simple. I need to make a cut across a series of faces that begins at a specific edge. Here I made a mspaint art to show you:

http://i456.photobucket.com/albums/qq284/pellaamarilla/wtfblender.jpg

Thx I worked hard on it. As for the topic at hand, please tell me there’s a way blender can do this. Btw I tried boolean subtract and it makes a big mess with extraneous edges going in random directions. Not to mention that booleans shouldn’t be needed for something this simple. In the ideal case, I’d like to be able to exactly specify the endpoint of the cut as well, but that may be asking for too much.

/smartass

For blender 2.49b, switch on snapping and select vertex as the snap option. It is the magnet icon on the 3d view header.
Demo: http://www.screencast.com/users/blenderwho/folders/Jing/media/72b78868-1a24-49fe-91b8-25ae18f0b02b

Oh wow. The manual says mesh snapping only applies to transformations. Anyway thanks.

on a side note, for cuts that aren’t limited by the existing topology, there is the ‘rusty knife’ script, but I don’t know if there is a recent version or not.