Analog Equivalent Circuit of an easing function
I know basic rise-/fall slew circuits, but I expect this is different.


For a one dimensional signal it's very basic - it's an RC low-pass filter. Here is the transient response to a step change: -



Trace A is the step input and trace B is the output as indicated in the circuit below: -



And, just in case you have any doubt, you can take an analogue RC filter and digitize it as follows: -



So, if your digital algorithm matches the IIR one immediately above then you have the equivalent of an RC filter.