Switch in analogLib has Vopen and Vclose. I found this. Vopen must not be equal to Vclose. Otherwise, Spectre will announce an Error.
Then, I've done the following simulation. The schematic is below.
<1> Vopen=2V; Vclose=-2V.
<2> Ropen=100 Ohms; Rclose=1 Ohm.
<3> Is=1A; Vin=VCtrl.
VCtrl is sweeped from -3V to 3V. Then Vout=Rout*Is, which is equal to Rout in value. The simulation result is below.