Expand the 3D surface into a 2D plane--IF Statement
 

Hi everyone,
I want to expand the 3D surface into a 2D plane.
The math transformation piecewise function is like this:
if y>=0
y=48*arcsin(y/48)

if y<0 and x>=32
y=16*arcsin(y/16)

if y<0 and x<32
y=16*arcsin(1) +32-x

（x,y are coordinates for this 3D surface.）
I have written a Macro as follow:
#!MC 1200

$!ALTERDATA EQUATION = "{Y}=if({Y}>=0,48*ASIN({Y}/48), {Y})"

$!ALTERDATA EQUATION = "{Y} = if({Y}<0 && {X}>=32, 48*ASIN({Y}/48),{Y})"

$!ALTERDATA EQUATION = "{Y} = if({Y}<0 && {X}<32, 16*ASIN(1)+32 -{X},{Y})"


But it is wrong!!!
I really need your help on this Macro.
Thank you so much!!!