Performance

Performance may be slow for large projects that contain many objects and data when exporting from Revit Architecture and importing into 3ds Max.

To improve performance, limit the model geometry you export. Try using a section box or hide categories of model elements that you do not need in Revit Architecture and set an appropriate level of detail level.

Cameras

• Multiple Cameras: Revit Architecture exports only one camera to FBX, which corresponds to the active 3D view. This means only the current Revit 3D view or camera, imports into 3ds Max as a 3D camera view.
• Camera Frame and Optical Center: The 3ds Max FBX Plug-in does not support the cropping region and optical center of Revit cameras. However, the field of view (FOV) or perspective of the Revit cameras is correct in 3ds Max. So, this does not translate precisely in 3ds Max if you modify your Revit camera by resizing and/or offsetting the cropping region (frame) of your 3D view in Revit. This is caused by a combination of FBX not transporting the render resolution settings, and a limitation that the 3ds Max camera model does not support an optical center.

Geometry

• Pivot point (object center): Geometry exported from Revit does not have a correct local pivot point or center, as is normal when you create objects in 3ds Max. Object centers are offset from the object, but have a correct position in global space. If you are not manipulating or animating the position of your objects in 3ds Max, this offset has no impact.
• Massing objects: Massing objects in Revit are not supported, and do not export to FBX.

Hidden Revit elements

Groups

Revit Groups have no 3ds Max equivalent so the 3ds Max FBX Plug-in ignores all Revit Groups. For example, if you export lights within a Revit Light Group, the 3ds Max FBX Plug-in converts the lights but loses any grouping.

Project units

Revit calculates system units in Imperial units (Feet and fractional inches). When Metric units are set as the “Project Units”, Revit dynamically converts the Imperial units into Metric units, in the UI. This means that FBX always exports in the actual system units, Imperial (Feet). There are no issues in working with Metric units in Revit and 3ds Max, but this results in an Imperial (Feet) FBX file, that automatically converts to Metric (Meters) on FBX import into 3ds Max. When you use an Imperial (Feet) Project Unit in Revit and Feet System Units in 3ds Max, no conversion is needed.

For more on Revit units, see Unwanted scaling in 3ds Max.

Daylight Portals

Revit uses daylight portals differently from 3ds Max. They exist in both applications but because they are calculated differently at render time, 3ds Max FBX Plug-in does not import these daylight portals into 3ds Max. Doing so would result in low performance. This performance issue is because Revit systematically creates daylight portals for each individual window, and for each side of the window. This does not affect the rendering performance of Revit since only windows relevant to the camera view are only calculated at render time.

However, 3ds Max renders all daylight portals systemically. Therefore, it is better to create one single daylight portal for an entire wall of windows manually in 3ds Max as you would normally when you work in 3ds Max. This results in better performance and gives better visual results.