Setting animation preferences

Before we start building nCloth scenes, we need to just change a couple of quick preferences. Most importantly is the playback rate of the timeline. It's really critical that we don't skip frames in the timeline. It's possible that if you have your timeline settings set to real-time, then, when you try to play back a dynamic simulation, it will break. Real-time is not what you want. You need it to play every frame, and not to skip any frames. If it skips frames, then your simulation is going to break, and the reason for that is that Maya's dynamics are so-called history dependent.

What happens on a particular frame -- lets say frame 10 -- depends directly upon what happened on the frame before it; frame 9. If the playback engine skips frame 9, then the data on frame 10 is going to be bogus, and your simulations is going break. We just have to make sure that we don't play back in so called real-time. We can do that in a couple of ways. One way is to go into the Preferences. Window > Settings Preferences > Preferences, and in Time Slider, we have got the Playback options here. You'll see the Playback speed is at currently Play every frame, and that's good; we need that.

If we were set to real-time, then again, we would have problems. That needs to be set to Play every frame. Below that you will see Max Playback Speed, and I've currently got that set to Real-time. What that means is, in a lightweight scene the playback engine will not exceed the current time base, which is 24 frames per second. But in fact, the default is free, which means that in a lightweight scene -- one that's not very computationally expensive -- the playback rate will be too fast, and you may not notice.

It's just important that the playback speed never exceed 24, or whatever your current time base is. Otherwise, what you see in the viewport will not correspond to what you get when you render it. That wants to be set to Real-time. I've also chosen to choose Update view All, meaning that we will see playback in all the viewports, regardless of which one is selected. You could also change that setting of the Playback rate from the timeline itself by right-clicking, and choose Playback speed > Play Every Frame > Max Real-time.

This is the setting that you need 100% of the time when using dynamics, and any other setting is either going to cause your dynamic system to break, or for it to play too fast, giving you a bogus idea of the animation timing. And also, just to make sure that we know what our current playback rate is, we want to enable the frame rate in the viewports, and that's done in the Display menu, under Heads Up Display, and I'll to enable Frame Rate, and now it appears down here in the lower right-hand corner of the viewport, and if I press play, you'll see that it's giving me a readout of approximately 24 frames a second.

Those are critical settings that you need to have enabled for all dynamics, and nCloth is certainly dynamics, so we need to have those turned on.