Export Revit to Maya

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Introduction

There are several methods to export 3D models from Revit to Maya. There are three main file types that you can use:

  • FBX
  • DWG polymesh
  • DWG ACIS solids


FBX
creates triangulated polygon meshes; each object has its own shader. Material properties from Revit are not preserved. No Layers.
DWG polymesh
creates triangulated polygon meshes; you can create rules that specify how objects should be assigned to layers. The same editor also assigns shaders based on categories. Material properties from Revit are not preserved.
DWG ACIS solids
creates NURBS surfaces for most objects; you can create rules that specify how objects should be assigned to layers. The same editor also assigns shaders based on categories. Material properties from Revit are not preserved.


FBX

Pro: Each object becomes a polygon mesh in Maya. Reasonably fast.

Con: Each object has its own shader. You need to clean this in Maya. No layers.

DWG polymesh

Pro: Layers and category-based shaders enable you to have a structured model which is easy to work with, especially for more complex models.

Con: Each polygon mesh is exploded in separate objects for each surface (a cube-shaped object is exploded into 6 separate objects), which makes handling e bit more difficult.

DWG ACIS solids

Pro: surfaces are nicely grouped. Layers and category-based shaders enable you to have a structured model which is easy to work with, especially for more complex models.

Con: NURBS are less optimized for texturing and rendering.

Recommendations

If your aim is to export your model to Maya for visualization purposes: for simple models, use FBX. For more complex models, use DWG polymesh.

General preparations

The most important step when exporting your model from Revit to Maya is the preparation. It is paramount to optimize your model:

  • Only export the part of the model you need
  • Keep the level of detail as low as possible
  • Optional: organize your model before exporting


Selecting which part to export

Exporting must be done from a 3D view. The configuration of the view also determines which parts of the model are exported.

  1. Use the Visibility/Graphics Overrides to configure which types of objects are visible.
  2. You can use a Section Box to cut your models to specify which part of the model should be exported


Level of detail

Especially furniture, fixtures, plants, trees and railings can cause your 3D model to become quite large and heavy. Only include those objects if you really need them.

When you use highly detailed families, the resulting model may become too heavy. The level of detail of your objects in Revit should be geared towards the intended use in Maya: for conceptual visualizations of your entire model, your Revit model shouldn't be too detailed. If you want to make an interior visualization or a visualization of a part of your building (detail), it is no problem to use high-detail objects and families.


Export as FBX polygon mesh

  1. In Revit, activate the 3D view that you set up using the guidelines above
  2. Click the Application Button, under Export, click FBX.
  3. Choose a path and a file name to store the FBX file.

Importing FBX in Maya

First you have to make sure the FBX plugin is loaded:

  1. Window » Settings/Preferences » Plug-in Manager
  2. Locate Fbxmaya in the list and check both Loaded and Auto load.
  3. Click Close.

Then you can proceed to import your model:

  1. Open a new scene
  2. File » Import...
  3. Browse to the location where you saved the FBX file. Select the file.
  4. Click Import

You're model is automatically scaled to the units Maya is set to (default: centimeters), which means 1 unit in Maya is 1 cm.

Export as DWG solids

DWG Export Dialog in Revit
  1. In Revit, activate the 3D view that you set up using the guidelines above
  2. Click the Application Button, under Export, click CAD Formats, click DWG Files.
  3. In the DWG Export Dialog, in the Select Export Setup section, click the ... button. The following dialog opens:

Revit modify dwg export layers.png

In the Layers tab you can set up which object types are arranged in which layers. The column Color ID determines which material is assigned to the object. This enables you to use color coding to structure the objects in your model.

In the Solids tab you can select how objects are exported. Choose one of the two options:

DWG polymesh solids

Revit modify dwg export solids polymesh.png

  1. Select Polymesh.
  2. Click OK
  3. Back in the DWG Export Dialog, click Next.
  4. Select a location and file name for the DWG export.
  5. Click OK


DWG ACIS solids

Revit modify dwg export solids.png

  1. Select ACIS solids.
  2. Click OK
  3. Back in the DWG Export Dialog, click Next.
  4. Select a location and file name for the DWG export.
  5. Click OK


Importing DWG in Maya

First you have to make sure the Direct Connect plugin is loaded:

  1. Window » Settings/Preferences » Plug-in Manager
  2. Locate DirectConnect in the list and check both Loaded and Auto load.
  3. Click Close.

Then you can proceed to import your model:

  1. Open a new scene
  2. File » Import...
  3. Browse to the location where you saved the DWG file. Select the file.
  4. Click Import

You're model is automatically scaled to the units Maya is set to (default: centimeters), which means 1 unit in Maya is 1 cm.

Rotate the imported model 90 degrees in Maya

You will probably have noticed that you model is rotated. This is because Maya uses the Y-axis as the up-axis, while DWG by default uses the Z-axis as the up-axis. Rotating your model shouldn't be too much of a problem:

  1. In Maya, open the Outliner (Window » Outliner)
  2. Select the RealDWG_Shape_rep node
  3. In the Channelbox enter -90 for Rotate X and press enter.
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