I've got this illustration of a block diagram published in a book. It's quite a basic concept of surface metrology but I've been inspired by it, I've redrawn the diagram using LaTeX with another layout and add other steps that for me are missing in the original. How would you define such drawing? I was thinking to use the sentence "modified after" but actually I completely redrew it and add new features to the drawing, so I've not modified an existing drawing but re-drew it, even though I've not simply re-drew it but also add content. Should I use "re-adapted after" or "inspired by"? Is there any guideline regarding drawing attribution?
There are some guideline regarding drawing / figure attribution. I found some here which seem quite reasonable. You might want to look for the specific guidelines of the publisher you are targeting.
In your case, where you adapted an original drawing, the link referenced above recommends to put the reference to the original in the caption:
Figure X. Descriptive phrase that serves as title and description. Adapted from Book Title (page number), by Author First Initial. Second Initial. Surname, Year, Place of Publication: Publisher. Copyright [Year] by the Name of Copyright Holder. Reprinted [or adapted] with permission.
Author Surname, First Initial. Second Initial. (Year). Book title: Subtitle. Place of Publication: Publisher.
Which begs the question: do you have the explicit consent of the original authors to adapt their diagram for your specific needs ?