I've noticed that when I create an outside gear, 12PD, 120tooth, 20deg outside spur gear, and then create the same gear, only inside. I expected that they would match each other.

They're not even close. The diameter is different as well as the teeth arc lengths. The only thing that matches is the tooth spacing.

Does anyone have an answer as to why? I asked my VAR, and the reply was that the gears are only meant as a visual guide.

In this case, I'm not sure which one is even close. Using one for mating and measuring leads to errors with the other??

Thanks for any help or explanations

Vic