Thanks for your support . I will to follow for your suggest.

  Yep, that's is exactly i want. I want to do that, purpose my app is  join many 3D objects in a layout to an object then export to DXF format can be import it to the AutoCAD tool but I'm not sure  3D object format and dxf file format to convert them. That's very hard for me, could you suggest to me any library do that. Thanks you and sorry my english not well

That was not actual my question. I want to ask after import multiple object 3D to android app(example: show it...) then i want export all to a object with dxf format? So, can i do that? Thanks so much!

Hi all, i'm beginer with the jPCT. I have a problem when export from 3D object to the autoCAD format (dxf).
But i'm not sure can be that. Please suggest to me some way do it! some example do that thanks all!