Well.... there are a lot of aspects about that.
Remember that Mudbox is an sculpt software capable to work with very heavy subdivision models, and hi polycounts.
So, on first stage: which is the aproximated polycount are you exporting a character done in mudbox to the website?
You are exporting the Level 0 basemesh with normals, and AO extracted and applied?
Or perhaps you are exporting the hi poly subidivided meshes and you didn't know that.
Which size are the texture maps,(if there any), for your character models? Are them a lot of and so heavy?(2k, 4k?).
Give us some more clues to help you in the possible.
Regards:
Sergio Mengual
3D Artist-3D Generalist-3D Character Artist
https://www.artstation.com/artist/sergiomengual
https://www.facebook.com/Sergio3D2D/
https://www.youtube.com/user/sergiomengual
