How is modern animation made?

Probably just painting, background, photography, splitting a mirror and so on. It is a frame-by-frame animation and a frame-by-frame painting. 24 frames per second, usually two frames per picture, with frames added in the middle. Sometimes 1 frame a picture. Of course, there are three or four frames or more.

Being an animator is also very hard. I remember that in Japan, the average animator earns money by the hour. The more time he spends, the more he earns, but the income is not high, which is similar to that of Japanese animators. But people like Kyoto Animation and Ghibli are similar to normal jobs, with fixed wages and holidays, which are better than the former.

Painting is mainly about drawing the movements of characters, but everything will move anyway. As the name implies, the background is like the sky in your painting. Photography is to make the animation move and add some special effects to the lens. Split shots are similar to switching shots, mainly because of the plot requirements. 3DCG is 3D animation.

It seems that Flash is mainly used in animation. I didn't notice it. Of course, 3d max maya is also used.

To tell the truth, I really can't say a word or two about this matter. After all, animation needs a lot of things, and I can't say it.

An animation, from production planning, director and screenwriter design to background drawing, animator, photographer and synthesizer, has everything. There are many people involved in the middle, each with a division of labor. If you really want to know the detailed process, you should look up the information.

The above is personal information (not very detailed, of course) and is not authoritative. It is recommended to check the relevant information in more detail. I typed a bunch of words and found the explanation unclear. After all, there is too much information.