A fairly difficult drawing, but pretty easy once you get the hang of things. Come with me as we go through the steps needed to get these curves and tangencies in isometric using autocad. Please note that I do not go through the steps for constructing isometric circles, but those videos are linked here.
• AutoCad Tutorial: Isometric Projectio... - How to draw an Isometric Circle
• AutoCAD Tutorial: How to construct 2 ... - How to draw External tangents
• How to: Construct an Isometric Circle... - How to construct an Isometric Circle using the Approximate Method
• How To: Construct an Isometric Circle... - How to construct an isometric circle using the Ordinate Method.