Hi,
Trying the latest version released, I saw that there still is an issue with geometry between Transmutr and sketchup. Actually, things are not visible in Transmutr (but there in sketchup), and the other way around also.
Beside, the smoothing groups looks also better in Transmutr than in Sketchup.
ps : the model is this one https://free3d.com/3d-model/mercedes-benz-sls-53003.html