Use the CV Curve Tool, turn on Snap to Grid up top on the right hand side, then click to create a point, now click for the next point, then keep clicking and you will see a white line appear, click until it completely goes away, now hit enter, there's your straight line You don't have to use Snap to Grid, I just use it because it's easier to work with things anchored to common points and lines
Darkon
Red bellows of flame have blackened my stones
Convulsing my frame and cracking my bones
Hell's dragons of steel who roar in their chains
Crawl into my caves to suck out my veins.....
-The Mountain P.F.M.