I saw on this forum that the toolbar was available for version 16.  What do you have to do to turn it on for TCv19?

If "Surface Modeler" is similar to other IMSI/Design plugins, you probably need to go through a "Start Up Options" dialog via the Windows "Start" menu. See if V19 is listed. If not, then Browse for the TCW19.EXE file, but it's doubtful that will work. They may need to update some Surface Modeler files so that it is recognized by V19.

John, have you used this plug-in with V18?  If so, how well has it worked for you?

I don't have Surface Modeler, but assume it is installed like their other 3rd party tools.