What to Use for a 3D Explainer Video
A 3D explainer, the kind with simple objects, a moving camera, and type beside the picture, is…

A 3D explainer, the kind with simple objects, a moving camera, and type beside the picture, is two jobs. Something has to build and render the 3D. Something else has to cut it and put the words on. One program can do both. Most people who finish these films do not use one program for both.
Blender for the picture
Blender is free, and it is the tool to learn if you do not already own a 3D app. It models, lights, animates, and renders. A product-design app such as Solidworks draws parts for manufacture. You can make a picture in it. You will spend the year fighting a tool that was not built to light a scene or render a camera move. Skip it for this film.
Give yourself a small finished shot before you start the explainer. A single object, lit, with a short camera move, rendered to frames. The public Blender beginner series built around modeling a donut is a reasonable way to get there. After that, the explainer is the same skills on purpose-built models.
After Effects or Premiere for the film
Render the 3D as frames or a ProRes file. Bring it into After Effects for the callouts, the lines, and the type, or into Premiere if the type is simple. Blender can draw text. Doing the type in After Effects keeps the 3D render, which is the slow part, out of every wording change.
A year is enough to finish a simple explainer this way if the models stay simple. It is not enough to become a character animator. Keep the first film to objects, a camera, and words.
