A room polygon drawing can be modified at anytime. After choosing this tool you should tap a corner, and hold your finger on the screen. As long as you move your finger on the screen the particular corner will follow it. When you release your finger from the screen, the corner will remain at its new location.
The move corner function also has a snap functionality, you can set it while the function is activated. Three main options are available, Normal snap, No snap and Snap to 90. in Normal snap mode you have the option to snap the corner angle to 15, 30, 45, 60 and 90 degrees (and their multipliers). This means if you set e.g. 60, than the wall starting from the corner you are moving will highlighted in blue when the next cornerâ€™s angle is 60, 120, 180, 240 or 300 degree.
There is a third use of this command, you can also resize wall openings with it. Select the Move corner, tap one endpoint of the door or window to be resized and swipe your finger. The wall opening will grow or shrink accordingly.