Hi Bob,

> While testing the ability to fillet or chamfer the diagonal
> edge of a triangle I assumed that connecting 3 lines in the
> shape of a triangle would result in a plane?

Yes, that should normally be the case that 3 connected lines will form a planar triangle.

Could you post the model file where you created these diagonal edges so I could take a look at it?

Another way to draw planar shapes at an odd angle is to use the View > CPlane command to set the construction plane to align to where you want to draw. That will then reorient the Top/Front/Right ortho views to be looking at that particular plane so while that cplane is active drawing in the Top view draws on that plane.

Some more info on this here:
http://moi3d.com/2.0/docs/moi_command_reference5.htm#cplane

- Michael