Hi Andrei,

> I can not make front and back both visible at the same time, because they messed up.

Drag one of the images in the Top view so that there is a little bit of space between them rather than both of them occupying the exact same plane, that should then help them display better when they are both turned on, there won't be any "z fighting" if they are slightly separated from one another.

If you want to switch the background image transparency between 0 and 100% with a shortcut key this script will do that:

script: /* Toggle background image transparency between 0 and 100 */ moi.view.backgroundImageTransparency = (moi.view.backgroundImageTransparency == 0 ? 100 : 0);

- Michael