Let’s look more closely at how to get some motion going. We have added some joints automatically and it allows us some real world motion properties.

Inventor has added the following joints to our assembly.

Dynamic Simulation 08

The spherical joint acts as a ball and socket would and the Point-Line you can think of as a spherical joint but it can run along an axis that it has been assigned to.

When working in DS and creating joints it is essentially about giving a part degrees of freedom.

With the spherical joint you do not have any tranverse freedom, only radial in the X,Y and Z directions. We can see this in the properties of the joint.

Dynamic Simulation 09

In the above screenshot you can see that the dof 3(R) is active. It also highlights in the modelling area (2) which axis it is revolving around.

If I run the simulation using the Simulation Player, we can see that when the ball drops it runs straight through the other balls.

Dynamic Simulation 10

To simulate contact we will use the 2D force joint. We will use the 2d sketch that we used to create the ball as the loop of the curve.

Dynamic Simulation 12

After inserting this joint when we run the simulation the ball then hits the second ball and it simulates as it should. You can see a link to the video I made using screencast.

Here is the link: http://autode.sk/1Vk3l9D. I would like to give credit to Jonathan DeRoner from GrabCAD for the model of the Newtons Cradle.