I have never used Arcad or Cycas CAD and do not know which Linux program is best. I had used LinuxCAD for a few minutes once and the commands seemed to be much like using AutoCAD. If I remember correctly it offered support for pen plotters but only minimal support for inkjet printers. Perhaps that may have changed by now. Of course for a real drawing a pen plotter would probably be better (if that is still the dominant technology for creating blueprints today). LinuxCAD claims that it can read the native AutoCAD dwg files and can also handle dxf files. It says that it can be used to create 2D or 3D drawings. It seems to have quite a few features. I am not sure how it compare to Arcad or Cycas but here is the link:
http://www.linuxcad.com
Are you interested in architectural drafting or mechanical drafting or what? There are also some other CAD programs listed on the webpage below that lists equivalents of Windows software in Linux. I do not really know which one is best or how well they compare to AutoCAD. The CAD programs are near the bottom of the webpage:
http://linuxshop.ru/linuxbegin/win-l...en/table.shtml
So anyway, I do not know much about Arcad, Cycas CAD or LinuxCAD.
