Squat depth confusion

[matze]

I swear to god, I read the book!
But I keep on being confused about how to detect proper squat depth...
I look at the hip creases but just don't know what point to pick on those lines to see if this point is below the top of the patella...
And what point I think works for people with longer, thinner thighs, seems to not work as well for people with shorter, bigger ones... Because I would detect the apex of people with shorter and thicker thighs further up the muscle belly? (see picture 1 & 2)

The red lines in the following pictures are, what I think, level with the apex of the hip creases, I usually refer to. That would mean that squat depth in picture 1 and 2 are just parallel?
Picture 3 might be good?
If I may (if not, please edit), I add the illustration on page 7, blue book.
The squat depth in the right picture again just seems parallel?
Arrow B just points at the hip crease, but not at the specific point of reference?, since that point would be at least an inch too low?
But the apex line again would be a bit too high?

The green lines just mark another theory... but properly detecting a point on the hip joint seems less likely to be "the truth".

small.jpgtall1.jpgtall.jpgbook.jpg

[Martin Shenfield]

Point A is the top of the patella. Not the top of the lady's quad. Point B is the hip crease. Point B needs to drop below point A and below parallel to the ground.

I am not an SSC and I'm autistic so I may very well be wrong, but I believe it's about parallel, the top of the patella and the hip joint as identified by the apex in the crease of shorts or pants, and not about the size of a person's quads.