Question: can inkscape open cgm files?
Answer: Inkscape natively supports opening or importing many different formats, such as SVG, SVGZ (gzipped SVG), PDF, EPS, and AI (Adobe Illustrator) formats. And, as of version 0.91, Inkscape can import CDR (CorelDraw) and VSD (Visio) natively. With the help of extensions, Inkscape can open a number of other vector formats.