A rendered a 3d character created in 3d studio max and exported as .m3g file .On the emulator it blows up the size of the character and the rendering becomes very slow on the device.
What could be the problem.
What is the per pixel conversion ratio between 3d studio and the emulator.
There is no such thing as a "per pixel conversion ratio" when exporting -- it is all dependent on your transformation matrices, camera and projection parameters, as well as the screen resolution on the phone.
Possible causes could be that you are not viewing the model in 3ds max through the camera in your scene, or that you don't have a camera in the scene at all. You would then see the model from a different viewpoint in max; and in the latter case, some exporters substitute a default camera at the origin.
If you're setting the camera in your application, make sure that the coordinate values in 3ds max are roughly in the range you expect in your application.