[Lua Script] i need a function to this

[perdigs]

i need a one function to check a radius position
for example

x= character
0 = radius

000
0X0
000

if in the pos 0 is not walkable he check another pos of this radius
if is walkable this return the pos in x,y and z of the radius pos and if all pos
is not walkable return the X position...

please help me to make this script.