I am not a JAVA specialist, but it seem that this Link to doc can help to read directly blend file. Don't know how difficult it is to make integration into SweetHome 3D but as BLENDER is one on the main sofware used to create furniture, I guess this could be a nice addition.

regards

I found that link and it seems that some BLENDER current dev are trying to mimic SweetHome ease of use:
http://www.youtube.com/watch?v=hW0Ac2cK1Ss [=D>]

I am impressed by the rendering result

Sorry for late reply ... Well I don't know I seen this rendering engine that seem to be also based on JAVA. I guessed it could be easy to integrate. I don't know how much work is required to change the engine but I guess it's not an easy task. Why I think it will perform better than JAVA 3D .... hum ...

Would it be possible to see http://jmonkeyengine.org/ integrated to Sweet Home 3D to improve real time rendering ?