Bicycle chainring

Are there competing spline styles to lock the ring to the crank arm? Looking at some photos online makes it look like there are different styles.

Hi,
that is correct, I need the one in the first picture its for a Cannondale SI crank.
34t
Regards Lars

Attached a pic

I've never seen a CAD model with these splines on it, but it does not look too hard to duplicate.
Are you able to take accurate measurements of an existing ring or crank arm?
A flat bed scanner with a reference scale can also be pretty handy for this type of work.