# Rainbow Cloud Baby Mobile Tutorial – Part 2

For part 2 of this 2-part SOLIDWORKS tutorial, the finished assembly was used to run a motion analysis of the mobile using mates and motors. You will need to have completed part 1 of this tutorial before following on with this part. In part 1 we created some simple baby mobile parts that we used to create an assembly in this tutorial part. You should have the empty mobile, a rainbow and a cloud hanging part. If you haven’t downloaded the file for this tutorial, you will need this for the music box parts. These are available to download here. By the end of part 1, you should have the empty mobile, a rainbow and a cloud hanging part.

The music box was designed just for the rendering aesthetics and analysis, rather than a realistic representation of how it would be made. When downloaded this comes in 3 parts, the music box, hook and winder; these are all assembled with the mobile hangings and mobile parts. The hook and winder are mated into position so that they attach to the music box, but also have a concentric mate which allows them to move when motors are applied. When starting the assembly, the main music box is dropped in first, the reason for this is that the first part dropped into an assembly becomes a fixed part. Having a fixed part makes it easier to mate everything onto this main part which you want to stay in one place. It also makes it easier for creating the motion analysis, as without this fixed component the whole mobile assembly would just fall from the gravity motion study element. In reality the mobile would hang onto a mobile arm attached to a cot, but for the purpose of this model, we need to have a fixed part to mimic this scenario. When following the tutorial you will notice a sketch on the mobile hook part was added to mate the string of the mobile onto it, this sketch helps to keep the mobile in one place rather than relying on motion analysis contacts, it also speeds up the motion analysis calculations.
For the motion analysis, I chose to use motion analysis for my study type as it takes the physics of the assembly motion into account. This takes everything into account for movement including gravity. For this analysis, gravity is added, to the y axis, it is pulling down. I didn’t need to apply any contacts to this analysis as I had everything mated into position. The only other motion elements to add are all the motors. Motors were applied to the music box winder, and the hook so that as the winder moves, the hook move in tandem while turning the whole mobile. The only issues I found is that if I didn’t apply further motors to the mobile hangings they would remain facing the same way as they moved around on the mobile. So to make the mobile move more realistically, I applied a rotation motor to each mobile hanging at different speeds. SOLIDWORKS Visualize was used to render the snippet of the animation below.