Hi Igor - if you have a lot of other things in the way, my best recommendation is to hide them so that they don't interfere.

Don't try to struggle so much with a lot of things in the scene - try to clear things away earlier and free things up.

But other than that, a couple of things you can try:

- Disable object snap so that it will not kick in. You can do this either with a click or if you wish to set up a keyboard shortcut, then go to Options / Shortcut keys, and enter in this for the command:
script:moi.drawingAids.objectSnap = !moi.drawingAids.objectSnap;

It is also possible to set up a kind of "enforced" ortho line - to do that, drag out a construction line and hold the mouse down on the little tag that shows up, and pick "Project next point":

Construction lines overview:
http://moi3d.com/1.0/docs/moi_command_reference10.htm#constructionlines

- Michael