Hi Hernando, Chimera displays the graphics as fast as it can up to 30 frames per second. If the displayed model is complex or your graphics card is not fast enough the actual frame rate will be slower. The rock command moves the model in fixed angular steps no matter how slow the rendering rate, and never skips any steps, so it will just appear to rock slower if the computer can't maintain 30 frames per second. In contrast movies are always played at a fixed speed (typically 30 or 25 frames per second). Movie Recorder records every displayed frame, and these get played back at a higher speed by your movie player software. To make the movie rock at the rate you see in Chimera you can first see what rate Chimera is rendering at using menu entry Tools / Utilities / Benchmark and turn on the "Monitor actual frame rate" at the bottom of the benchmark dialog. If it says you are getting 20 frames per second, then use that number in the Movie Recorder movie options panel when you encode the movie. That will be stored in the movie file and players will play the frames back at 20 frames per second instead of the usual 30. Tom