The blender knife tool is really handy, and works under edge modifications much better.
Anyway here's a mini tutorial for modelling a gun (Blender)
Open it up, you'll see a cube. Hit tab to go into edit mode. After hitting tab, click "select faces", it's the button with a triangle on it between the 3D screen and the lower panel, on the right.
hit "a" to deselect all, if it doesn't, hit it again. Then right-click on the top face. Hit "e" and if it prompts, hit "select region", then hold the ctrl key and drag the mouse up. (you might want to be in a different view, I use numpad 1 for top and 7 for front, I think that's default)...
Now that you've extruded it up a bit (doesn't matter how much, you can change it later), hit "a" again and select a side face, then hit "e" and extrude that, until you have an L shape.
That should give you a basic shape of a gun... and to be honest, the only extra thing you'd need to do is switch to scaling (or just hit "s", then "x,y, and z" to lock the axes you're changing) and change the scale of the portruding area.
Man, I need to make a video of this...
Note, if you screw up and hit right mouse or undo after extruding, you probably did NOT erase the extrusion, you just moved it back to where it started... so just select it and move it again. This is because when blender extrudes, it actually duplicates a face/vertex/whatever, then moves it. So hit delete instead of undo when you *** up
The last mini tutorial thing you should know is in the lower right, there's a set smooth modifier in the panel, if you don't see it, click your middle-mouse button between the bottom panels and drag it to the left. "Add Modifier" then "Subsurf", 2 levels is usual. It'd smoothe it out.
And last but not least, shift K is the knife tool.
Other handy notes: B is box select, and "alt B" is clipping select, which is EXTREMELY HANDY if you have lots of stuff, and only want to select one region of vertices. I used it a few times already, as a beginner...
Man, you guys really should read the manual... just dedicate an hour a day to it, it's extremely handy, well worth the time and effort in my opinion.
And yes, about that tutorial vid you could use, I might get to it soon. Any suggestions or things you want? I'm not a pro, but I do know what practically every button does that's not animation related... (and have to reread some, hehe)
Signed
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