Compatibility across products using FBX

This topic describes the compatibility of various components that Mudbox supports through the FBX format. Unless otherwise noted, these components are completely compatible between Maya, Mudbox, and 3ds Max, or the data is converted or interpolated so that the results are functionally equivalent from product to product.

Polygonal meshes

In general, importing polygonal meshes using FBX are completely compatible in Mudbox, Maya, Flame, and 3ds Max.

On import	On export
Grouping hierarchies - Model hierarchies that exist in a Maya or 3ds Max file are collapsed when the mesh is imported to Mudbox using FBX. Top level transformations and pivot points on the mesh are retained. Mesh smoothing - Any edge smoothing (Maya) or smoothing group (3ds Max) information is not retained when the FBX file is imported to Mudbox.	Only the current subdivision level is exported when exporting a mesh from Mudbox using FBX. Any sculpt layers not locked to that subdivision level are baked into the resulting mesh on export. The current subdivision level becomes the base level for the exported mesh. If you want to preserve the separate sculpt layers, turn on the Export Sculpt Layers as Blendshapes preference in the FBX preferences (Maya.)

On import

On export

Grouping hierarchies - Model hierarchies that exist in a Maya or 3ds Max file are collapsed when the mesh is imported to Mudbox using FBX. Top level transformations and pivot points on the mesh are retained.
Mesh smoothing - Any edge smoothing (Maya) or smoothing group (3ds Max) information is not retained when the FBX file is imported to Mudbox.

Only the current subdivision level is exported when exporting a mesh from Mudbox using FBX. Any sculpt layers not locked to that subdivision level are baked into the resulting mesh on export. The current subdivision level becomes the base level for the exported mesh.
If you want to preserve the separate sculpt layers, turn on the Export Sculpt Layers as Blendshapes preference in the FBX preferences (Maya.)

Blend Shapes (Maya) or Morph Targets (3ds Max)

(Maya) - The vertex position information contained in a blend shape target is converted to a sculpt layer when transferring between Maya and Mudbox via FBX. The Weight attribute on the blend shape becomes the Strength property on the sculpt layer when the FBX file is imported.
The Export Layers As Blendshapes preference must be turned on for sculpt layers to be exported as blendshapes. Sculpt layers are converted to blend shape targets (Maya) or morph targets (3ds Max) when transferring between Mudbox and these 3D applications using FBX. See FBX preferences.

Cameras

(Mudbox) - After import to Mudbox, right-click the new camera that appears in the Object List and select Look Through. You can lock the imported cameras to prevent accidental dollying, tumbling, and so on.
(Maya) - FBX only exports the non-default cameras from Maya. The default persp, top, front, and side cameras are ignored. If you are exporting your Maya scene using FBX and want to retain the default camera related information when you import it to Mudbox, you must first select and duplicate the default Maya perspective (persp) camera (View > Select Camera, Edit > Duplicate), and then select the duplicated version prior to exporting your FBX file.
(Maya) - Maya cameras match better in Mudbox if the Fit Resolution Gate camera attribute is set to Vertical prior to exporting an FBX file from Maya.

Curves

When Export Curves is on (by default) in the FBX preferences, selected 2D (ViewCurve) and 3D curve (Curve) objects are included in the exported FBX file.
Note: 2D curves (ViewCurve objects) are exported in normalized space (scaled between 0 and 1 or -1 and 1), so they may appear smaller than expected when imported in another application.

Image planes

(Mudbox) - Image planes are an attribute of cameras that get exported with the cameras when exporting an FBX file. After import to Mudbox, right-click the new cameras that appear in the Object List and select Look Through to view the image planes. You can lock the cameras associated with the image planes to prevent accidental misalignment.
(Maya) - If you are need to export image planes with cameras from your Maya scene using FBX you must first select and duplicate the orthographic cameras associated with the image planes (View > Select Camera, Edit > Duplicate), and then select the duplicated version prior to exporting your FBX file. In addition, setting the Fit attribute to Vertical in the Placement section of the Image Plane attributes will ensure a better match when imported to Mudbox.
(Maya) - Maya provides an option to either embed or reference the images associated with an image plane when exporting as FBX.

Note: Image planes are not supported and are ignored in 3ds Max.

Joints

Prior to exporting your model from Maya or 3ds Max, ensure that the FBX export options are set so they export the skeleton and skin weighting data with the model. For example, in Maya the FBX Exporter Options window, ensure that the Include preference setting has Animation and Deformed Models options turned on, and that the Skins and Blend Shapes options are also turned on.
Joints and skin clusters (joint weights) are imported with the model when the FBX file is imported to Mudbox (provided the Import Joints preference is turned on). This data can be used in conjunction with the Pose tools for posing and deforming models. For more information, see Posing overview.
Vertices can be influenced by a maximum of four joints in the joint hierarchy (the four strongest influencing joints). Beyond that, the imported weight information is ignored. To ensure that joint weights transition smoothly for imported models, the Smooth Joint Weights preference can be adjusted as required. For more information, see FBX preferences.
Joint hierarchies where meshes have been parented into a joint are not supported. For more information, see Troubleshoot posing.
Portions of a mesh may not display in the 3D View if the number of joints exceeds a specified maximum amount. This limitation only affects the mesh when using the pose tools, and is not apparent when sculpting or painting. The mesh can still be posed but you’ll need to select either a paint or sculpt tool to view the entire mesh. The maximum number of joints a mesh can have before display limitations occur is dependent on your computer’s graphics card: NVidia: 256; ATI: 75. For more information, see Troubleshoot posing.

Material textures

Textures assigned to the selected objects shading material, including layered textures (3ds Max refers to these as composite textures) are imported as discrete paint layers when the FBX file is imported to Mudbox (see supported shading material attributes described above). The textures are assigned to the equivalent paint layer channel in Mudbox.
Layer blend mode attributes for layered (composite) textures are supported to a limited extent with FBX import. The Normal, Multiply, and Add blend mode settings are supported. Any other blend mode settings that exist for the layered textures are set to Normal blend mode when an FBX file is imported to Mudbox.

Paint layers

When you export a Mudbox scene using FBX, Mudbox creates a subdirectory titled <filename>.fbx-files to store any associated paint layers (textures). If you prefer that the FBX file reference the paint layers (textures) in the same directory as the .mud scene (<filename>-files), turn on the Reference Textures from .MUD File preference in the FBX preferences.
By default, paint layers on the exported model (including the background color) are saved as discrete textures when exporting from Mudbox using the FBX format. If the importing 3D application supports it, the textures usually appear as layered textures on the model's shading material. For example, within Maya, Mudbox paint layers appear within the shading material as layered textures.
Layer blend mode attributes for layered (composite) textures are supported to a limited extent for export. The Normal, Multiply, and Add blend mode settings are exported with the material. Any other layer blend mode properties that are set for any layered textures in the file are set to Normal when an FBX file is exported from Mudbox. When this occurs, the following warning is displayed: “Paint Layer Blend Mode: <blend mode name> is not supported in FBX, it will be converted to the Normal blend mode”.
If the Flatten Paint Layers On Export preference is turned on when exporting (see below), the resultant flattened texture will look correct regardless of the blend mode settings.
Some 3D applications do not universally support multiple layered textures within a single texture channel. In these circumstances, turning on the Flatten Paint Layers On Export preference is recommended. This causes the paint layers to be merged into one texture per channel during export. The flatten operation also includes the background color for the material.
Normal Map channels that contain multiple paint layers (and have the Preview As Paint Layer property turned on) will automatically be flattened to one paint layer when exported as FBX. This occurs because some 3D applications do not support the rendering of multiple normal map channels in a material.
Bump/Displacement Map channels that contain multiple paint layers (and have the Preview As Bump Layer property turned on) will automatically be flattened to one paint layer when exported as FBX. This occurs because some 3D applications do not support the rendering of multiple normal map channels in a material.

Quick Select sets or Selection Sets

(Maya) Quick Select sets and Selection Sets appear in the Object List within Mudbox when the FBX file is imported to Mudbox.
(Max) Selection Sets appear in the Object List within Mudbox when the FBX file is imported to Mudbox.

Sculpt layers

The Export Layers As Blendshapes preference must be turned on for sculpt layers to be exported as blendshapes. Sculpt layers are converted to blend shape targets (Maya) or morph targets (3ds Max) when transferring between Mudbox and these 3D applications using FBX. See FBX preferences.
Keep in mind that sculpt layers are locked to a specific subdivision level, so only the sculpt layers locked to the currently active subdivision level will be exported as blend shape targets. Any other sculpt layer information that exists on any other subdivision levels gets baked into the base mesh when exported using FBX and not exported as a blendshape.
The Lock property on a sculpt layer is ignored by FBX.
Any layer masking that exists in a Mudbox file is baked into the blend shape target/morph target when exported as an FBX file.
When the Visibility property for a sculpt layer is turned off, the blend shape target’s weight is set as zero in the FBX file.
Export layers as blendshapes works on selected faces.

Shading material

By default, any assigned materials and textures that exist in an FBX file are automatically imported into Mudbox with the mesh. If you do not want materials and textures to be imported with the mesh, turn off the Import Materials and Textures preference (Windows > Preferences > FBX). The default Mudbox Material is assigned when this preference is turned off.
The default shading material of the imported or exported object may be converted to a material with an equivalent appearance. Material attributes that are supported by Mudbox when importing an FBX file are: Diffuse, Specular, Gloss, Bump Map, Incandescence, Reflection Mask, Reflection Map, Reflection Strength. When exporting an FBX file, Normal Maps are also supported.

UV texture coordinates

Only one UV set is supported for import by Mudbox; the first UV set.