soft selection and maxscript

Hello
I made a little script to drop selected vertex on picked object.
I would like to use soft selection to have a smooth result.
I read a lot of threads, but I don't understand how to...
If somebody can help. Thanks
-----------------------------------
(
vvv = $
rollout pick_box_test "Target surface"
(
pickbutton chooseit "Intersect me" width:140
on chooseit picked obj do
(

for v in polyOp.getVertSelection vvv do
(
pta = (polyOp.getVert vvv v)
RRay = ray pta [0,0,-1]
aaa = (intersectRay obj RRay)

if aaa != undefined then
(
PPos = (intersectRay obj RRay).pos
polyOp.setVert vvv v PPos
)
else
(
RRay = ray pta [0,0,1]
aaa = (intersectRay obj RRay)
if aaa !=undefined then
(
PPos = (intersectRay obj RRay).pos
polyOp.setVert vvv v PPos
)
)

)

)

)
createDialog pick_box_test

)
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