I am curious to know how the figures in these popular introductory physics textbooks are made. As examples of what I mean, see the posted figures and my comments, all from various editions of Serway and Jewett (I think).
Look at all of these color gradients throughout the metals, and the imitations of lighting on the spheres. Notice the relatively realistic nature of the force scale and pullies.
Notice here that we have proper, LaTeX-like font on the vectors.
Wow. So many complex shapes, good water drawings, and the ability to annotate the drawing freely.
Lastly, we see more extremely complicated, realistic objects, like the ship and the mountain. But this isn't just pictures, it's clear that the software used has a very precise coordinate system in it, as evidenced by the kinematics drawings overlaid.
I am aware of the other posts on SE recommending drawing softwares such as LaTeX, TiKZ, pstricks, aymptote, matlab, mathematica, etc. But I highly doubt these figures were produced in any of these. My suspicion is that the publishers have some specialized software for this task. So what is that software? Does anyone know?
And a side question, when a textbook gets as popular as Serway & Jewett, do the authors still make the figures? Or do the publishers take over that job once the book exceeds some amount of popularity?
Update: I emailed and got a response from Professor Randall Knight, author of Physics for Scientists and Engineers: A Strategic Approach. He told me that the publisher, Pearson, makes his final drawings, and that they use illustrator.
Another data point is that Michael Stone made his own figures for his book Mathematics for Physics: A Guided Tour for Graduate Students published by Cambridge Press. And he used a less known software whose name I can't recall.
I also posted this question on the graphic design SE and got a useful answer: https://graphicdesign.stackexchange.com/questions/71327/how-are-these-modern-physics-figures-made