For my latest scimatics project, I had to create a 3D object in an app called Tinkercad, calculate the surface area and volume of my design and figure out the ratio of it. I decided to make a sword, mainly because when I was messing around with the app, I ended up putting shapes in the shape of a sword. My sword is composed of: Rectangular prism x1, Cylinder x1, Sphere x3, Hemispheres x2, Triangular prism x2, Pyramid x1 and looks like this. 
The first thing that we had to learn was how to calculate the different volumes and surface areas. Here are some formulas. 
After we learned our formulas, we had to learn how to use the app: Tinkercad. It was actually quite easy to use. It’s pretty much just drag and drop.
Thats it for now. Comment things that you would like me to make with Tinkercad.
Bye.