Problem with Snapping So, I'm working on this house with oblique walls.

I can't properly make the vertex just move along the Y axys and snap to the lower line, as it snaps along the Y axys but doesn't stop exactly ON the line.

Any easy way of doing this? Since I'll have to do it a lot of times.
Blender allows you to set a custom orientation for transformations, but, unfortunately, does not provide custom orientations for snap projections.

However, if you enable the Mesh:TinyCAD add-on, (included in 2.78) it will do what you need, and some more.