Hello,
it’ me again 
i am trying to work on revit but actually i noticed that there’s lot of difference between previews.
Did someone encountered the same problem and know how to fix it??
Thank you very much in advance.
Elisabetta
Thank you. Actually i notice that was the Dynamo Preview Node. If i disable the specific Node Preview without disble the Preview of the ImportInstance.ByGeometries, it works fine.
Thanks
Elisabetta