In my personal ability, it is generally like this: the simplest: draw a sketch on paper, then scan it on the computer and color it with PS.

It's a little more complicated: draw a sketch with paper, then turn to CAD to make a PDF standard drawing, and then color it with PS. It's a little more complicated: turn to CAD step as shown above, and then turn to 3D to finish coloring. Limited ability haha, in fact, the final results of the three methods are the same. Personally, I think the biggest advantage of computers is that there are many things, and it is not necessary to have plug-ins or high-version software. Forget what I said. )