Direct Motion 4: Keeping Objects Together

One of the main challenges with motion is keeping objects from changing in unexpected ways as they move.The two files below illustrate the problem. Drag points A and B and change the view angles. What are the differences between the two files?

The demo Moving Claude will show you how to make the first file, and will illustrate some of the techniques by which you can make files that "hang together". An alternative to the demo is to download the file and work out how it was constructed: the demo how constructed (related file moving_Claude1)will show you some features of Cabri 3D and some strategies that will help you to work this out.

Bsically, if you want an object not to change as it is moved, it must be constructed in relationship with the point to be animated.

One way to do this is to construct a circle or sphere of constant radius centred at the point to animate and then use this circle as the basis for other objects. See the demos Circle tool and Sphere tool for details of constructing such circles and spheres.