question about moveing models gzdoom

so I know how to make moveing cameras with interpolation points but I was wondering if someone could explain how I can get a 3d model of a ship for exsample to fly across a sector. anyone with advice? I use gzdoom builder and doom builder 2 and gzdoom. I seen in videos 3d models following paths but im not sure how its done.

I guess my question is how do I get a 3d model to follow a path like in this video.

http://www.youtube.com/watch?v=mzdml88eY-E

I know the guy who made that video ;) and I can tell you that there is nothing special going on.

Models in GZDoom are attached to normal actors. You can think of a model as simply being a set of clothes being worn by an underlying actor. Anything you can do to make a normal actor move can be done to an actor that uses a model because the model actor is just a normal actor wearing a model on top.

In the case of that particular video, the models are just normal projectiles being fired across the skybox from map spots using a script. The projectiles have been set up in a modeldef lump to use the Quake2 Viper model.

thanks for the help. I see what you mean . its a actor after all so I should be able to maby find some sort of flags that may help or something. trying to get the effect of a ship takeing of upward then forward or landing. Edit: I figured out how to do it with the actor mover class thanks for the help