How to import .ctb file (pen assignments) into GstarCAD ? FEATURED Tue, Apr 12, 2016 Pen assignment, .ctb, plot 0 2 23063 4.5/5 (2 Votes) Click on File > Plot Style manager. Alternatively by using shortcut command STYLESMANAGER. Paste the pen assignments(.ctb) file here and relaunch the PLOT command. Read More