sketchup questions!

[SeaBass]

I'm trying to draw a brace in the corner of a bent but when i draw that 45 degree line the entire corner become a triangle and after that it stays there so i have a triangle in permenance in the corner that you see thru!!! So how can i draw my brace without having that problem?

Seabass

[witterbound]

Draw another line that represents the inside edge of the brace.  For example, if the brace will be a 3x5, that is 36" from the post and the beam, draw your first line at 45 degrees from 36" to 36".  Then use your measuring tape tool to draw a parallel 45 degree dotted line that is 3" inside the first line you drew.  Then draw that line.   Then delete the rectangle that lies inside your second line.