Carl:

Fabulous! Thank you so much!

I searched for this issue but could not find it, so thanks for answering!

-- Kevin

Addendum:  I never used Windows 7.

I have the same problem, but my Maple version is 18.

In my case I know it isn't a syntax or user error because I was using a code that, among other things, plotted several space curcves successfully in Maple 17 on Win Vista, XP and then also on Maple 18.00 on Vista and XP (same code).

As best I can tell, this problem started with Windows 8. The problem still exists in Windows 8.1. Today I updated to Maple 18.02 and experienced the same problem of not showing spacecurves.

Then I found this forum topic. When I added "linestyle=solid" as suggested above, it now works.

Coincidentally, the same code also plots arrow vectors in 3D, and it no longer did so after switching to Win 8 & 8.1. Ironically, when I added "linestyle=solid" to the spacecurve command only as stated above, the arrow vectors also reappeared for some reason (even though I didn't change the command line that created the arrow vectors).

Thanks for the help, TomM!

@Adri van der Meer 

Fabulous!  Thank you so much, Adri!

Kevin...