I have an animation where I have a camera sweeping around a room. It has been running fine all the time I have been working on it, but all of a sudden when I hit play and watch the animation it slows down considerably. It doesn't seem choppy, but like its in slow motion. 1 second of animation takes about two seconds in real time. Any suggestions of what is wrong?
There is an option called "All Frames" that is usually enabled by default. If you disable that option, it will skip frames in an effort to keep the playback as close to realtime as possible: http://www.cactus3d.com/AllFrames.jpg
There is a point, though, when your scene gets to heavy, that with that option disabled it will be too choppy. That's when you have to start rendering editor previews to view the animation in realtime.