A big difference between MEMS layout and IC layout is the use of unique, irregular shapes. Unlike conventional CMOS IC design, MEMS design utilizes a much broader variety of geometries, due to its wide application in mechanical, optical, magnetic, fluidic and biological fields. This two-part paper describes how and why support and ease of use for implementation of irregular shapes, including curves and all-angle polygons, is a critical criterion differentiating MEMS-oriented CAD tools from conventional IC-oriented tools. (Part 1 focuses on layout editing; Part 2 on verification.)