Check the license for each model or pack depending on how you purchased it.
The path for the licenses from the items bought in the store is...
C:\Program Files\The Game Creators\FPS Creator\licenses
Quote: "
Grant of Licence
In consideration of the Customer's promises herein (including without limitation the Customer's obligations in clause 7 of this Licence Agreement) the Seller hereby grants the Customer a personal, non exclusive, perpetual, non transferable, royalty free licence to:
modify Assets and integrate Assets in "Commercial Games" (as defined below) created using FPS Creator, FPS Creator X10, Dark Basic Professional, Dark GDK or in other Games; and ...."
"
"created
using FPS Creator, FPS Creator X10, Dark Basic Professional, Dark GDK
or in other Games"
Looks to me like other engines is ok.
Although, if you are not using FPS Creator, FPS Creator X10, Dark Basic Professional, or Dark GDK to make your games, then SHAME ON YOU!