In the game, you create control points that Camtrace3D will use to generate the curve.
A specific command bound to the 0 key allows you to extract the coordinates of the in-game view. That is, the actual position of the camera in demo mode.
Example for ETPro :
In Camtrace3D, you can import the coordinates by specifying the folder where your .epcp files (<ETpath>\EtPro\Pos) are located (For Quake 3, import them from <quake3>\Defrag\Pos\MyPos.dfcp).
The program creates a curve by linking these points.
The « Create » button in the Script tab generates the camera path into .cfg files. Specify a name and a location and validate : the curve is now ready to be executed. Load the game from Camtrace3D and press the appropriate key to execute de camera script.