i need a software that i can draw a 3d object

hai
i think you can use ansoft hfss which will be very useful for all 3D drawings and eleectromagnetic simulations.

hi,
if you just want to draw a 3d object then GMSH can serve you
it is a 3D finite element grid generator
http://www.geuz.org/gmsh/#Download
its free!
u can then use the geometry file generated by gmsh in your simulator
regards