[ODE] how to glue bodies together ?

[XFred]

Hi there,

I have some trouble to fix parts of complex bodies.
My application has nothing to do with realtime but aims on physics precision (so I use DOUBLE precision).

I tried to use fixed joints but the results are unreliable (as it's written in the latest doc). 
I can workaround the problem, but I'd like to know if there's a better way.

Thank you for your support.

-- 
Fred D.