Insering a datum point of a face

[yanger11]

I tried a few methods but is there any way to insert a datum point of a curved surface 9in order to attach a spring to that surface. i tried projecting onto teh surface but the surface is very irregular and the datum point does not project where I need it to

 

[corus]

You could try partitioning the surface with two planes so that the intersection point is the point you need.

corus