.j3o binary consumes about 4x more space than corresponding .blend file

I have a “house.blend” file of size 3MB. I used the application “convert to j3o binary” to convert it in .j3o format. Now to size of “house.j3o” is 12MB. I guess contents of both the files are more or less similar. So why there is considerable file size increase?

while it’s not the perfect answer, here some information:

Well depending on the model, it might be (at least partly) additional tangent buffers.

In general the jme native format is optimized for speed, not for size.