Graphics Programs Reference
In-Depth Information
2. Take note of the frames on which you set important keyframes for the axe's position
(for example, when it recoils and releases at frame 10 and when it hits the target at
frame 25). Select the axe's top node (axe), and delete its translation animation. Select
all three Translate attributes in the Channel Box, and right-click to display the short-
cut menu. Choose Break Connections to delete the animation from those channels.
The axe now spins around, and it and the target recoil at the moment of impact, but
the axe doesn't actually move.
3. Keep the motion trail in the scene for now to help with the timing you've already
created.
4. Select the top axe node, and then Shift+select the path curve. In the Animation menu
set, choose Animate
➔
Motion Paths
➔
Attach to Motion Path
r
.
5. In the Options window, turn off the Follow check box.
The Follow feature orients the object on the path so that its front always points in
the direction of travel. Because the axe moves backward in anticipation before it's
thrown forward, Follow would cause it to turn around twice, so turn this option off.
Now the axe will follow the curve end to end from frame 1 to frame 60. Of course,
you have to adjust the timing to it it, as before.
6. Select the motion trail, and move it down in the window to get it out of the way; but
keep it lined up vertically with the path curve so you can figure out the timing again.
The ile
axe_path_v1.mb
in the Axe project will bring you up to this point.
7. Select the top axe node, and open the Graph Editor to see the axe's curves. The rota-
tion curve is still intact, although the translation curves are missing. Click motion-
Path1 in the Channel Box to highlight it; the motionPath1.U Value curve that took
the place of the translation curves appears in the Graph Editor. On the left side of the
Graph Editor, select the motionPath1.U Value curve to display only that. Zoom into
it. (Press A to view all.)
8. The curve is an even, linear curve from 1 to 60. You need the axe to hit at frame 25,
so move the end of the curve to frame 25 from frame 60.
9. Retime the backward movement. Scrub the animation until the axe moves all the
way back (frame 4). Using the Insert Keys tool ( ), insert a keyframe at frame 4.
Select the animation curve, click the tool, and MMB+click the curve to create a key
on it. You can MMB+click and drag the cursor to place the key precisely at frame 10
before releasing the mouse button.
10. Move this new keyframe to frame 10 (the frame where backward movement origi-
nally ended).
11. Scrub the animation, and the timing is just about right. You'll have to adjust the
tangents a bit to make the axe move more like before, but the movement is essentially
there with path animation.
