True Scale vs Primaris

[Lucerne]

 

when truescaling, never, repeat never extend the shins, anatomically it's the daftest thing 

Hmm...  The Vitruvian Man seems to disagree with you.  You can see where the model's right knee matches up with the diagram's right knee, and the lower leg on the model is consistent with the length of the diagram's lower leg.  If anything, the shin section is still slightly too short with an extension.

 

 

And that's because the upper leg is under the soft armor where it meets the pelvis, not just the plating.  Most of the reason you're confused is the average model's stance is awkward, so lengthened shins make the lower leg look too long, but the boot also has a platform to it, meaning the foot isn't flush with the ground, and the thigh armor gives the illusion that the upper leg is shorter than it is. However, both sections need to be more or less equally extended to result in a properly proportionate leg compared to the arms and an extended torso.  The legs of humans also attach on an angle, not straight up and down, so a single plate of thigh armor cannot encircle the entirety of the upper leg without impeding the range of motion.  Space Marine armor "solves" this by incorporating the "soft" armor at the joints, which is largest and most pronounced where the leg meets the hip, because unlike an elbow or knee, the leg has a significantly higher range of motion. The shoulder's weak point is covered by the pauldrons. Mk 8 and Primaris armor supplements the pelvic joints with additional plates.

 

The whole basic Space Marine model was borked, proportionately. It's why all these modeling projects came about in the first place.  Big long gorilla arms, big heads. It wasn't like all the modelers just started arbitrarily making the legs and torsos longer, lol.  I did the models originally with just thigh extensions, until by observation and anatomical comparison I realize that the legs were still too short compared to the arms, and the discrepancy was now below the knee. 

 

For further reference, and I invite you to test if on your own legs, from the top of my ankle to the bottom of my kneecap is 13 inches.  From the top of my kneecap to groin is a little over 10.  About a 1.3:1 ratio. The outside length of my upper leg is closer to 14, or roughly the same length as my lower leg. With shin extensions, the lower leg and outer thigh lengths are almost identical (to the extent I can accurately measure in millimeter fractions). An unmodified shin is, unsurprisingly, roughly 1 full mm shorter on a model roughly 40mm in height (bottom of foot to top of head),  leaving it vastly out of proportion. 

 

I'd love to hear what you think about the new CSM proportions, incidentally.