First of all, I'm just getting started with Solidworks so this may be an easy task but I sure haven't figured out how to do it. I'm trying to draw a line from an arbitrary point that is on the line formed by the intersection of two planes to another point that is the intersection of 3 planes. For instance, let's say I have a cube. I want to draw a line from the a point on the line that forms the intersection of the top plane and the front plane of the cube to the point that is the intersection of the bottom plane and the front plane and the plane of the left face of the cube. I want my line to be on the front face of the cube. I can draw a line that, depending on the view I've selected, looks like exactly what I want. However, if I rotate my model, invariably the endpoint of the line is out in space somewhere and not on the front face. Also, is there a point at the intersections of the 3 planes that can be selected without me having to do anything or do I have to physically put a point there? Ditto for a point on the line formed by the intersection of 2 planes. Thanks in advance for the help.

I'm not sure I followed all that, but you should be able to set coincident relations between the endpoints of the line and all of the planes (one at a time).