4D object casts a 3D shadow, we as 3D objects cast 2D shadows. We have no reference to what 4D is so we cannot view a 4D object directly. Carl Sagan in his TV show Cosmos has a wonderful explination. At first, the Paperpeople would see nothing. Then, at the first instant the ball crossed their piece of paper, theyd see a little dot. Then, as the ball continued moving through the piece of paper, theyd see a circle expand from that point to a larger circle. Finally, as the ball began to leave, theyd see the larger circle collapse back to a point and then disappear. So, people percieving 2 spatial dimensions would experience a 3 spatial dimension object as a series of 2D objects spread out across time.

Blender renders 3D objects using a method called raytracing. In general it is a much more accurate technique for rendering and allows for you to render things much more realistically. Any sort of 3d animated movie renders its frames using ray tracing. Video games simulate 3d enviroments by using textured Polygons. Video games also frequently make use of bump mapping which allows you to make your textures look like they are popping off of the polygons. No, you dont need d drawing skills. You can create 3D objects based on their measurements. You can arrange them to create any object in the universe. However, you will need good layout skills and good photography skills, in order to compose your 3D scenes to make them look right. Fortunately, you can learn those skills as you go. 60 reference book, so its not exactly free. That said, you should keep working on your drawing skills. He teaches techniques for drawing 3D objects with pencil and paper.