I know this is an old post to bump, but in case someone finds it my new plugin was written to do this exactly:

http://sketchucation.com/forums/viewtopic.php?f=323%26amp;t=61884

Hi everyone,

This is my first post and first plugin. I had a problem where I wanted to select all the edges that form a roughly straight line across an object, but not the other lines. Having looked around a few other people had the same problem and there wasn't a plugin for it so I did a crash course in ruby (Thanks for all the resources) and hacked this plugin together.

It's dead easy to use:

• select 1 edge of the stuff you want selected
• Press: Tools/Extrapolate Selected Edge
• Fill in the threshold you want. (0 is select all edges, 1 is only perfectly parallel edges) Default is 0.85 which selects stuff following a smoothish line. Experiment to find what is right for you.
• Hit ok.
• Done

It's pretty quick, but as I say, 1st plugin and hacked together from zero knowledge of Ruby before yesterday, but I thought it would be good to share.

Enjoy,
Dom

New selection plugin