I am always having a great problem while modeling knees and elbows. Some people say put three loops on knee and some people say put 5??.. If i put too many loops then it collapse while deforming and when i put less then it won’t deform properly…
I just want to Know is there any effective topology technique for knees to deform naturally and which should look realistic while the character is on squatting positions.
I don’t think you’re going to get a solution that simply works out of the box; complex deformations like the one you show will require some tweaking. Some riggers will divide up the deformation across two knee joints instead of one and like you say, others will use a different number of edge loops in the original construction.
The answer lies in what you do AFTER the rigging - either painting weights, corrective blendshapes or influence objects. The knee and the flesh and muscle around it have a very complex structure that has a volumetric squash when the knee bends - the soft tissue of the upper calf squashes against the back of the thigh and pushes out as it presses toward the bone; no software will calculate that with the push of a button.
There’s no magic solution for these issues. Typically trial and error and lots of real world referencing makes the world of difference.