using a reference plane position in an equation

I am creating a part using loft, "morphing" one sketch into another, each
sketch in it's own plane. Is there a way to parametrically define the
dimensions of the current sketch based on the x-axis position of the current
reference plane? For example, if I place 10 reference planes, each parallel
to the right plane, and 50 mm apart, is there a way to know the absolute or
relative X (or Y,Z) position of the current plane, to be used in an equation
describing the current instantiation of that curve? As a simple example,
place a circle in the first plane, and I want each subsequent circle on the
10 reference planes to be of a radius equal to 0.95 * X-position +10mm.



Any Ideas?

 

If you use your first plane to offset each plane the offset dimension will
be equal to your x postion.
Or create a sketch in a perpendicular plane and use ordinate dimensions put
your zero dim at the origin off of a reference line and select each
subsequent plane. Then use thes dimensions in your equations. The thing
that sucks is it will ask you for each one if you want to use it since it is
a driven dim. I hate that.

Corey