Topic: Hans on tutorial: get hold of your tweens (intermediate level)
If you ever moved a bone and wondered why it animates over the whole duration of the animation, look no further! In this tutorial I’ll show you how to use the graph-mode timeline to time your tweens.
Before we get started:
Download and open the tutorial file
Select Animation Graph from the View menu, or press Command + 2
Understanding tweening
First thing first: tweening is how Dimp animates bones from one position to another. Select any orange joint, and look at the timeline:
In the timeline, a line turns from gray to dark. That's the line for the bone that we’ve just selected! Every little dot on the line is a keyframe. This is where the joint turns orange.
The graph shows how the individual joints move over time. One block (dark grey or light grey) in the timeline is a second. You'll see that this entire tutorial animation lasts just half a second.
Now back to that timeline, let’s take another look at these dots:
From the graph we can read that the selected bone will move to three successive new positions. The line between this points is what’s interesting: that’s the tweening magic.
Because between these points, Dimp will automatically animate the bone. From the graph you can see that the bone slowly moves to one position, then somewhat faster to the next, because the line turns somewhat steeper.
That’s an important thing to remember: the steeper the line, the faster the bone moves.
Adding a tween
With this dry stuff behind us, let’s add a tween. If you press the play button, you’ll see that the figure has his head low after landing:
Let’s make him turn his head up after landing. Put the playhead – that vertical orange line in the timeline – in the position shown in the screenshot above, at the time just past when the figure lands. You can do this simply by clicking or dragging in the timeline.
Now, move the head up:
You’ll see a new line appear in the timeline! And because that keyframe is selected the line leading up to it is yellow, too.
(Pro-tip: if the line wraps between the top and bottom edges, you can use your mouse’s scroll wheel to scroll the graph up and down)
Now if you play back the animation, you’ll see that this is not what we wanted. Instead of moving the head up after landing, it moves all the way from the beginning of the fall. Oops.
The solution
Why did that happen? Why didn’t Dimp animate from the part where we wanted it to? Because we didn’t tell it, of course!
Take another look at that timeline:
Dimp knows of two points. First, the position at which the head started, second, the position at which it ended. It then dutifully animates a slow transitions, which you can see by the shallow decline of the line.
How do we solve this? The solution is pretty easy. We need to give Dimp another point of reference!
First, move the playhead to where we’d like the head to actually begin moving:
The keyframe will be deselected and the line will turn gray, but don’t worry about that.
Give the head a swirl and see what happens:
A new keyframe is added, and you can see it in the timeline right as you’re dragging the head.
Now to make the head not turn until after landing, all we need to do is keep the line flat, because that’s when it doesn’t move. So, position the head so that there’s a neat level line in the timeline before it:
That’s it. Play back the animation and you’ll see that the had doesn’t move until after landing.
Another way
There’s another way you can achieve the same result. It’s really the same, but in a different order. First, move the playhead to where you want the movement to start. Click the joint to make it a keyframe. Now you’ve got that straight line to that point. Then move the playhead forward to where you want the movement to end, and move the bone to where you want it. Now the line goes from the point you’ve just made at the start of the movement to the end, like it should.
Wrapping up
I feel like this is a hard concept to explain. I’m going to make it easier to handle in future Dimp versions, but it’s going to be a big transition from Pivot or other frame-based apps anyhow.
If you have any questions or comments: down here!
