Pimples in rubbers

[Snek]

I have had this interesting question in my mind for a some time. Every rubber has some kind of pimples. Does it make difference If the ball hits exactly on one pimple compared to exactly between two pimples(or as far away as possible from every pimple)? What about short and long pimple rubbers? Why there even is pimples in inverted rubbers? Is there rubbers without pimples?

 

[_ak]

For inverted rubbers a flat layer over pimples reduces the difference. For pips out rubbers once in a while block may produce very strange bounce. I guess it's less when chopping.

 

[Tyce]

Having pimples between sponge and top sheet allows it to have more "give", as the pimples will bend and then snap back upright. This allows for more spin generation.
A pimple is not much more than 1mm in diameter, the ball is 40 of which maybe 15-20 hit the rubber. As such you'll always have contact with dozens of pimples at the same time. The difference between hitting dead center on one, or right between 3, should be unmeasurable.

(these numbers are rough estimates, the idea remains the same)