Ah yes, you mean when someone is being interviews and their name pops up at the bottom of the screen? These are called Keys. I did a video for my team
view it by clicking here. The cog, wrench, and W is done in 3ds max. I rendered it just standing still spinning in air. Then in after affects I added the lens flare, red tile bar, names, and animated the layer that was the spinning cog.
You need to render the 3d object along with a alpha channel. (this can be done by clicking render elements in the render dialog (hit f10) and then click "add element" then choose alpha.) After the video is done rendering there will be two videos that are rendered. One that has a black background and looks like your object (video), the other that is only black and white. (this is the alpha). In after effects you create a new composition. drag your video into the time-line then drag your alpha into it. Make sure the alpha is no longer see-able in the view port. What you need to do is set the alpha channel to a matte. Is is done by adding a matte key effect to the video layer and then choosing the alpha channel as the matte when the window pops up. Also make sure to set the keying as luminance.
(confused yet?)
Then what I did is I created a new composition and dragged my previous composition into it. within the new composition I made the names, the red tile bar, and the lens flare. This is a nice set up because then I only need to change the name of the person and not re-render everything from max.
(not done yet)
Then after I created all of that I exported the video format for each name in a video WITH ALPHA CHANNEL. This is done within the exporting menu. Then I open adobe premiere and slap the Key that I just created on top of the video that I want. If i exported with the alpha channel correctly the video wont become black, and the key will appear on top of the video.
(whew!)
PM me if you have any questions