What's Alt+B ?

I coding something today and used Alt + b as a hotkey. Since I could not remember what that was in Blender I went and checked and …well …what is that long gray thing that toggles on and off with Alt b. (values X,Y,Z and diameter?!?). Is it useful for something?

(2.46 & 2.49)

It is view clipping. Try dragging the box across part of an object.

Alt+B masks the area your working on. Say you take a cube and hit alt+b and go down the middle of the cube, now you’ll only see that area of the mesh

and how do you get out of it?..reveal?

Press alt-b again.

That’s a useful feature for working with big and complicated models. I have been using Blender pretty much every day since 1.8 and managed to never stumble across it. It found it’s way into 2.5 as well I am pleased to report, however the Ctrl + b physics baking menu did not (yet).

I find it very useful when it comes to weight painting as well. Cutting a head in half and looking inside to paint those hard to reach spots…works like a charm