This article explains how to draw a simple corner of a wall from an inside perspective.
Things You'll Need:
Things You Will Need
Draw a vertical line in the middle of the paper or screen.
Go to the bottom of the vertical line and draw a second line at about a 45-degree angle downward and to the right. It will look like a floppy "L".
Go to the bottom of the vertical line again and draw another line at about a 45-degree angle downward and to the left. Your drawing will look like an upside down "Y". A basic corner is done, but you can still take it a step further.
Go to the top of the vertical line and draw a line at about a 45-degree angle down and to the right.
Go to the top of the vertical line again and draw a line at about a 45-degree angle down and to the left. Now you have a corner with a roof.