All threw out the game u see like huge machinery like Pistons and experiments and reactors and huge machinery moving around. Is ther some pre made Machinery i can use. And if i where to make my own, would i need to use 3dsmax or sumthen? i know u have liek scripting lessons, i guess ill read that stuff it seems reaaly advanced 4 me tho. But if theres some premade moving machinery thatd be cool

there are all kinds of things for you to use if you right click and select new model.

I'm also going to be pro-active here and tell you that sometimes when you load in a model, it doesn't show up properly the first time. The easiest way to fix this is to put the model in, then press spacebar to copy it if it doesn't show up correctly, then delete the original one. The copy should show up correctly.

You can make your own. The only model type I know you can import without too much trouble is lwo.. lightwave object. That is a model from a program called lightwave. I haven't looked into others.

You can create in a seperate program, but them you'd have to create animation frames for the object in that program and export them along with the object into doom 3. Not quite sure how to do that yet.

Most of the machinery in-game seems to have been done with scripting. Best way to learn is to check out the script files - in the script folder - for the levels that had the machinery you saw moving.