When you export a DWG or DXF from Revit projects, materials are translated into a format that 3ds Max can understand. Revit creates materials in the same format as used by AutoCAD Architecture, VIZ Render and 3ds Max.
There are two kinds of materials associated with the Revit project; AccuRender materials and Revit materials. When a Revit material references an AccuRender material, the AccuRender material’s parameters are used; otherwise, the Revit material parameters are used.
There is an important caveat to this. AccuRender materials that reference a bitmap file are translated in 3ds Max without any problems, while AccuRender materials that are considered “procedural” are only translated at the most basic level.
Therefore, an AccuRender material that uses a bitmap image in the base texture definition will provide a more accurate translation to 3ds Max.
The Revit DWG Exporter puts embedded information on each object it exports. Amongst this information are identifiers specifying material assignments. Revit creates the same kind of material definitions used by AutoCAD Architecture, VIZ Render and 3ds Max. When imported or linked, 3ds Max uses this information to translate and maintain the material assignment to the resulting scene object.
Because the material identifier is embedded, if you opened the DWG in AutoCAD, you would not see the applied materials.
Revit offers many options for specifying a material to an object or class of objects. Likewise, there are many ways where material assignments can be overridden. The results you see in the 3ds Max scene, in terms of how the materials are applied, match what you see in the Revit model.
The exception to the rule would be if many of the materials are AccuRender procedural materials. In these cases, you will see only the diffuse color.
Material textures on imported or linked objects have the same appearance as within Revit or AccuRender. Of course, the exception to this rule is when AccuRender procedural textures are used.
When materials from Revit are viewed in the 3ds Max Material Editor, you'll notice that some settings are not translated or they are not set as you're used to seeing in 3ds Max. For example, if the texture map of a flooring material has a rotation of 45 degrees in the Revit project, the rotation setting does not translate when the model is linked/imported to 3ds Max. The rotation for the texture map is set to zero in the 3ds Max Material Editor.
The scale of material textures is of primary importance. The File Link Manager or DWG/DXF Importer attempts to read and translate the offset and tiling of the materials so the texture maps appear in 3ds Max as they do in Revit.
However, map scaling may differ because the Tile Size settings in Revit are measured in decimal feet or meters even if your Project Units are set to Decimal Inches or Millimeters. Once the model is linked or imported to 3ds Max, you can turn on Use Real-World Scale and match the Tile Size settings. The main thing is to pay attention to the Tile Size settings when you create the material in Revit.
As a example, let's say you've created a material in Revit that uses a brick texture map with an X: Tile Size set to 20 and a Y: Tile Size set to 16. If you open that material in the 3ds Max Material Editor, you will find that the Width and Height Size settings are automatically set to 20' and 16' respectively. The texture mapping will always be scaled correctly in the scene. How a material is displayed in the Material Editor depends on whether Use Real-World Scale is turned on or off.
As with models that are imported or linked from AutoCAD Architecture, there are special behaviors exhibited with materials assigned to linked Revit objects. The behavior is controlled by the Propagate Materials To Instances.
Once a drawing is linked or imported to 3ds Max, you can modify or replace the materials. The File Link Manager maintains a list of materials that it links to 3ds Max. If you change the properties of an assigned material while working in 3ds Max, the new properties can get overwritten the next time you reload an updated drawing, exported from Revit.
An important consideration in how many materials render is how they are “mapped” to the surfaces of the objects they are assigned to. This is especially important for materials that use bitmaps to define the diffuse color of a material, or the bump and cutout special effects.
After you've linked a DWG file that has been exported from Revit, you may find that some of the materials that were created in Revit could be used on new geometry you're adding while working on the model in 3ds Max. Reusing a material is often easier than creating a brand new one.
