one more problem

Hi all

I tried to import my file built by Autocad and Ac3d but my 3d shape is changed from the original shape.

What I did is that built it by autocad and export as .3ds file, and import to Ac3d to change to .wrl. In the AC3D, I setted (0.5,0.5,0.5) for position, and (1,1,1) for size. When I setted the size, the shape is changed
So, I tried to do with another file. It worked but only this file which I attached. I have no idea why the shape is changed.

Please recommand to me

Thanks