The outfit does not make the ass. It might enhance the ass or draw one's attention to the ass. The only thing that makes an ass hot, well, it would be the ass itself. Breaking it down scientifically, I think 3 factors must be measured-- firmness, size and shape.
Firmness equates to how well an ass maintains it's shape no matter what position of the other parts of the body. For firmness to be in play, we are talking about muscular rigidity to overcome the effects of body fat which creates flabbiness. For this, we have the wonderful BMI measurement to determine the fat ratio of the human body. Now we do need a little bit of fat to provide conturing and softness. After all who wants to see the ass of a bodybuilder with no ounce of fat. So in a highly scientific method to measure firmness, I conclude the firmness of the perfect ass would be somewhere in the 7-15% BMI range-- i.e. 7 to 15% fat ratio for the person in question.
Shape might be hard to define via mathematical equation. Also, this is probably a highly subjective area as some guys like bubble asses. Other guys prefer round assese, and still others like heart shaped asses. For this one, science can't help us other than to invoke the chaos theory-- to each his own.
Finally size, asses need to "fit" on the body from which they come. In other words, a nicely sized ass should be proportional to the bust and waist size of the girl in question. After all, nobody would consider a large ass to be a perfect ass (unless you are into that type of thing
). So, my mathematical formula is this:
X=bust size
y= waist circumference
(X+[y*1.33])/2= the ass size co-efficient. As an example a gal with a 34 inch bust and 26 inch waist would have an ass size co-efficient of 34.29 inches
Now take the ass co-efficient and compare it to the ladie's bust size. If the result is + or - 1 inch, you are in the perfect ass size range. The closer you get to the ass co-efficient being the same as the girl's bust size, the more "perfect" the ass size.
Now you take all three results to come up with the perfect ass. It is an ass on a lady who's BMI is between .7 and .15% with an ass co-efficient +/- inch or less of her bust size while invoking chaos theory to account for shape. Who says science can't help with the hobby?