Examples of 3D Figures in real life can be the Rubik cube or the Pyramid Of Giza.

3D (or 3-D) means three-dimensional, or having three dimensions. For example, a box is three-dimensional; it is solid, and not thin like a piece of paper. It has volume, a top and bottom, left and right (sides), as well as a front and back. You can turn the box around to view it from another side (called a face, surface or simply side).

A dimension is measurable in inches, microns, miles, kilometers, or any other unit of length.

The three dimensions are often called length (or depth), width (or breadth), and height. Some purposes use other words.

3D graphics are used to make video games or animated movies. Many calculations are needed to make pictures seem three-dimensional on a screen. Modern computers usually have a GPU (Graphics Processing Unit) to handle these calculations. 

 In geometry, pyramids and prisms are two different shapes. The main difference between a pyramid and prism is the fact that a prism has two bases, while the pyramid only has one. 

Or you could view a straight line as the generator. It moves in a circle to generate the surface. If the generating line is parallel to a perpendicular axis through the centre of the circle, a cylinder is generated. If the line intersects the axis, the generated surface is a cone.

A cylinder is a closed solid that has two parallel (usually circular) bases connected by a curved surface.

A cylinder is a geometric solid that is very common in everyday life, such as a soup can. If you take it apart you find it has two ends, called bases, that are usually circular. The bases are always congruent and parallel to each other. If you were to 'unroll' the cylinder you would find the the side is actually a rectangle when flattened out.