The program may be used free for 60 days. After this time Modeller warns you that key functions of the program have been disabled.
At this time you must register the program to continue to use it, or uninstall it.
The price at time of writing is,
To register by Cash, Cheque or Credit Card visit the following web-page
http://www.real2virtual.co.uk/modreg.htm
Or simply start Modeller and select the Help->Register menu item, followed by the Launch Explorer button. This takes you to the above page.
When you register the program you will be sent a User-Id and Registration Key by email. Select the Help->Register... menu item and enter these exactly as shown in the email.
You can now continue to use all functions of Modeller and Viewer. You are entitled to support by sending email to support@real2virtual.co.uk, with your User-Id and Registration Key in the subject line.