The File Link Manager and DWG/DXF Importer have many settings that you can adjust so you get the best results when linking or importing a drawing that you've exported from Revit. In this section, you'll find some recommended settings that you can use when linking or importing your DWG files. These settings are found on the Basic File Link Settings panel, the Advanced File Link Settings panel, the Spline Rendering File Link Settings panel, and the AutoCAD DWG/DXF Import Options dialog.
Use the Revit Preset for DWG Files
3ds Max includes a preset named “Revit” that you can use when using File Link to link a drawing that is exported from Revit. The Revit preset has many of the following suggested settings turned on by default. Or, you can use the Revit preset as a basis for your own customized Revit preset containing the settings you prefer.
The Revit preset can be assigned from the Preset list on the Attach panel of the File Link Manager. You can edit the preset by choosing the Revit preset shown on the Presets panel of the File link Manager.
If you plan on creating your own presets or modifying the Revit preset, use these settings to streamline the file linking process.
Turn on Weld and set a Weld Threshold
When Revit exports model geometry to a DWG file, objects are translated as multiple surface meshes. For example, a single wall is made up of 6 or more AutoCAD entities; each a polyface mesh with vertices that overlap their neighbors. When the meshes get linked to 3ds Max, the File Link Manager or DWG/DXF Importer recombines them back to a single object. However, when the meshes are recombined, their vertices are not welded, so you end up with a larger and less elegant model than expected. By turning on the Weld option and setting an appropriate Weld Threshold (like 0.1" or smaller), coincident vertices are welded together and the file structure is more efficient.
If you've set up one or more cameras in your Revit project, the File Link Manager or DWG/DXF Importer will recognize and link a camera when the Views (cameras) option is turned on. There is, however, a catch. Before you export a DWG from Revit, the camera view must be active and only the active camera will be exported.
Avoid Entity and Entity, Blocks as Node Hierarchy
Elements are occasionally missing Revit embedded data. When this data is missing, the objects are "derived" according to the Derive AutoCAD Primitives By setting. Deriving by either of the Entity choices will not, generally, give you the end result you want and could result in a scene in 3ds Max that contains a vast number of individual objects. In particular, these settings can cause issues with railing balusters.
Use Layer, Blocks as Node Hierarchy
The Layer, Blocks as Node Hierarchy derive by option, often gives the best results for linking DWG files, especially when the Revit project has other drawings, RVT links, linked to it. Combining by Layer (node hierarchies or not) is the preferred setting. RVT links get exported to the DWG as xrefs. If you want the File Link Manager to preserve color and material assignments of those objects, Layer, Blocks as Node Hierarchy is the setting to use.
Turn on Material Definitions and Assignments
These two switches are quite important when you've got materials assigned in your Revit project.
When the Use Scene Material Definitions switch is turned on, 3ds Max checks the scene for any currently used materials matching the exact same name as a material name in the linked DWG file. If a match is found, File Link does not translate the drawing’s material, and instead uses the material defined in the scene.
When turned off, the File Link Manager always uses the material definitions contained in the DWG file, and will overwrite scene materials with the same name, regardless of which objects the material is applied to. In addition, material definitions are always reloaded from the DWG file, so if you make changes to a linked material, then reload, those changes will be lost.
If the Use Scene Material Assignments on Reload switch is turned on, linked objects with a material already assigned to them in the 3ds Max scene will not have that material assignment changed. When turned off, linked objects have their material assignment ‘coordinated’ with the drawing, so that the two are in-sync.
Determine how you want Splines Handled
In your original project, you may have used 2D lines to represent joints between sidewalk pavers or as mullions separating sections of a curtain wall. The settings on the Spline Rendering panel let you use those lines more advantageously.
When you turn on Enable In Renderer and/or Enable In Viewport, lines are visible when you render the scene or are treated as selectable objects in the scene. You can also adjust the appearance of lines by having them display as radial or rectangular geometry.
