Checking the simulation with a Playblast

As we increase the quality of the simulation, the playback will be slower and slower in the viewport, to the point where we may not be able to correctly evaluate whether the animation is moving at the right speed. Currently what I've done is I have increased the Max Collision Iterations up to 40 in order to illustrate the problem. You'll see that my frame rate here is hovering around 10 frames per second. It's hard for me to evaluate this, and to be able to tell whether or not this is running at the right speed.

What I'll do is just simply make a Playblast. I'll rewind back to frame 1, and I'll go into the Window menu > Playblast, and let's go into the Options for that Playblast. This will just render a temporary movie out. I'm on Windows, so I want to use the avi format. You actually can use QuickTime; maybe we'll do that instead. I am going to choose a compressor, and since this is just a temporary movie, it doesn't really matter what compressor we use. I'll choose H.264, and just turn up the Quality.

Scrolling down a little bit here, the render size for the Playblast is determined by this Display size option. If it's set to From window, with a Scale of 0.5, what we'll see is it will render out to be a quarter screen video. In other words, it will find the size of this window, and then reduce it down to half of that, which is quarter of the area. Down here, we have the ability to save the file if we need to, and I'm going to actually opt to do that. Turn on Save, and I want to give it a name; I'll call this 03_02.

What I always do is I give the Playblast a name that exactly matches the name of the actual scene file. That way I know, if I've got lots of playblasts, I know which one is which. It's going to save into the movies directory in my current project. I'll go ahead and click Playblast, and allow it to play through. Now, I didn't set the range for the Playblast, meaning it'll just do the entire timeline. If I really need 600 frames, that's fine, but if I don't, I can actually just hit the Escape key, and that will kill the Playblast, and save what we have to disc.

We've got QuickTime installed here, so that just goes and launches automatically, and now I can play this back, and try to determine if my movie looks correct. Is the cloth moving the way that I want it to, now that I'm seeing it at normal speed? Now, I do want to mention that since I've got my frame rate displayed here in the window, that frame rate is actually being captured, but that's the frame rate during the creation of the Playblast, not during playback of this movie.

We could be pretty sure that this movie is actually playing back at the correct time base of 24. If you're not sure, you can actually go into the Movie Inspector in QuickTime, and check to see the Frame Rate, and it says it's a 24 frames per second movie. You will need to do this a lot, because it's really common that you will not be able to get real-time playback in the viewport, meaning that your fallback position is to make lots and lots of playblasts.