Getting workable .obj files / getting models into Mudbox

Hi there I’m having a massive pain trying to sucessfully get a model
into Mudbox.

So far the only time I sucessfully managed to see the model
in Mudbox it had over 1,000,000 faces for a structure that should
probably have less than 1,000 realistically.

(This was after using Blender to join the meshes, use the “remesh” modifier etc…, decimate
just destroyed the simple geometry such as basic flat step stairs.)

Every other time I just get some warnings and it crashes, is there any
basic method for getting .dae files into Mudbox normally, with or
without using an interim programme like Blender? Many thanks