HI there ,
Here’s what I found that could help you fix the problem:
Revit exports in Feet no matter what unit scale is used there. 3ds Max System Units are set to inches by default, which means that after transferring your Revit file to 3ds Max, all objects are scaled by a factor of 12. You can see that by selecting an object in Max, then selecting the Scale tool and you’ll find a scaling factor of 1200 in the type-ins at the bottom of the screen. This tends to mess up the texturing & tiling.
You can try importing the .rvt file directly into 3ds Max, this fixes the scaling issue.
If you absolutely need to use FBX, then set your max System Units to Feet before importing to match Revit’s scaling. Datasmith will handle the conversion from feet to cms when going to Unreal.
Also for best compatibility, avoid Revit’s “Autodesk Materials” prior to exporting to Datasmith, You’re better off using Scene Converter (from Max’s Rendering menu) to convert Autodesk Materials & Maps to something Datasmith can understand. You can use Scene Converter’s default setup, it works well.
Hope this help 