How to create a section in a portion of a view using straight lines and splines.

Hello,

I would like to create section views using straight lines, splines, and sometimes a combination of both. This was incredibly simple with Autodesk Inventor as in you simply drew a sketch on the drawing, set a reference surface and a distance to extrude it back and you were done. In Creo the best I can get is to either zoom way in and try to get it as straight as I can with the section tool (still looks horrible/wavy) or use 3D/Offset sections, but I have had issues ballooning parts when using these. Any insight would extremely helpful.