Chapter 33: Animating with MotionManager
Positioning the sled
Notice that the assembly has two parts: the track and the sled. In this animation, the sled goes
around the three sides of the sled and then stops. The first thing to do is to position the sled in the
track. I would make a coincident mate between the bottom of the side and the bottom inside face
of the track. Figure 33.13 shows this arrangement.FIGURE 33.13Positioning the sled in the track
Moving the sledNext, create the motion of the sled around the track by using key points. Move the time bar to the
next time you want to define the position of the sled, say 1 second, and then move the sled to the
position it should be in at that time. You can use either simple dragging to get the part where it has
to go, or you can use any of the options of the Move Component tool, shown in Figure 33.14.
When you move around the corners, remember that the sled is not going to follow an arc path; it
interpolates linearly between key points. You can, however, make it rotate and translate at the
same time. To do this from the end of a straight section, drag the sled with the left mouse button
(LMB) to its new location, and then rotate the part by dragging with the RMB to get it headed
down the next straight section. It is also recommended to use more key points when changes in
curvature are greater. So around the corners, it may work better if you can place key points more
densely than along the straight sections.The assembly on the CD-ROM has an animation stored in it. You might want to check it out for
reference.Attaching the camera
Create a new camera by right-clicking the Lights, Cameras and Scene folder. Use the steps I out-
lined earlier to attach the camera to the midpoint of the short side of the triangular sled, and target
the pointy end of the sled. Be careful to not position or aim the camera such that it is half buried in
the floor of the track or pointed at the floor. You want the camera to point in a direction parallel to
the floor.