Universal 3D

Use

You can import and view Universal 3D (.u3d) files. You can also save files to this format.

Adopted by Adobe, .u3d is required and used as the 3D publishing format in Adobe Acrobat. It can store meshes in two different ways: as a base mesh or as a progressive continuous level of detail (CLOD) mesh. Base meshes are not compressed, and do not include any level of detail. As such, these files are saved very quickly but are large in size. A progressive mesh is highly compressed and has a continuous level of detail. These files are smaller than base mesh files, however they take much longer to save.

A mesh can consist of multiple parts. For example, a mesh could comprise 80 vertices made up of 50 base vertices and 30 progressive vertices.

For further information about the .u3d file format, please see http://www.3dif.org Information published on non-SAP site .

Supported for Import

Cameras

Supported for Export

Cameras
Textures

Limitations

The .u3d format does not support pivot points so pivot point locations may be incorrect. To correct this, create a group node at the location of the original object pivot point. The original object appears as a child of this node. To rotate the object about its original pivot point, select the new parent node and rotate it.

Features

This format contains both import and export options. You can use them to customize the way in which your file is opened and saved.

Import Interface

Field	Functional Description
Import LOD	Imports LOD with the current file. Otherwise, the highest level of detail is imported.
Parse Metadata	Reads all metadata information including markups and material specular level metadata
Remove Append Data from Names	Removes the “##” and the number from the object names if the names contain these characters
Level of Detail	Used to define the Level Of Detail (LOD) settings. Universal 3D files store a continuous LOD; that is, every LOD is stored. LOD is a way of displaying models with different numbers of polygons depending on how close they are to the camera using the Level of Detail controls. This can speed up the rendering time by limiting the number of polygons that need to be drawn. Levels: The number of LODs that you want to import. The higher the number, the more information is imported. Create LOD if Mesh has Minimum Vertices: Creates the LOD if a single mesh has more than this number of vertices. For example, if you enter 200, LODs are created if a mesh has at least 200 vertices. Otherwise, no LODs are created. This is helpful where models comprise very small meshes with a small number of vertices, as LODs created for models such as these would be too small to be visible. Create LOD if Minimum Vertices in File: Creates the LOD if the total number of vertices in a file is more than the specified number of vertices Minimum Vertices per Mesh: Sets a minimum number of vertices requirement before an LOD is created. For example, the total number of vertices is 50,000, and the number of mesh vertices is 50. The LOD is not created if you import a file with a total of 47,000 vertices and at least 60 vertices per mesh. However, a LOD is created if the file contains a total of 55,000 vertices and at least 55 vertices per mesh. Note The level of detail (LOD) is created for a mesh if one of these two cases is true: 1. The number of vertices in the mesh is greater than or equal to Create LOD if Mesh has Minimum Vertices 2. The total number of vertices in the scene is greater than or equal to Create LOD if Minimum Vertices in File AND the current mesh has at least Minimum Vertices per Mesh vertices

Export Interface

Field	Functional Description
File Format	Defines the version to which to export the file ECMA 1st edition: Select 1st edition for more compatibility (all U3D readers support it) ECMA 3rd edition: Select 3rd edition. 3rd edition may be unsupported by some applications (like Acrobat 7). 3rd edition also has some improvements, so if your application supports 3rd edition, you should use it.
Mesh Compression	Defines mesh compression
Compression Quality	Defines the quality of compression. 1000 gives best quality, 0 gives worst quality Compression Preset: Compresses the file using one of the following options: Game: Predefined quality for games applications CAD: Predefined quality for CAD applications Custom: Provides access to the custom compression quality settings Vertices: Sets the compression levels for vertices Normals: Sets the compression levels for vertices Vertex Colors: Sets the compression levels for vertex colors Texture Coordinates: Sets the compression levels for texture coordinates
Texture Compression Type	Selects JPEG or PNG compression for textures
JPEG Compression	Exports all textures in the JPEG file format JPEG Quality: Compresses the JPEG files to the specified percentage quality Note If the JPEG option is not selected, the default texture format PNG is used.
Normals	Exports all surface normals. This option creates more appealing looking models but larger files.
Default Camera	Saves the default camera view in the file. For example, if you open a scene, rotate it, and export it to the .u3d format with this option selected, that view is used when you open the .u3d file.
Append Data to Non-Unique Names	Appends “##” followed by a number to all the non-unique object names in a scene. This creates a unique name for all the objects in a scene, as the .u3d format requires a unique name for each scene object.
Skin and Bones	Writes skin and bones information to U3D; not all scenes with skin and bones can be exported to U3D due to limitations of the U3D file format. Note All bones must be children of the skinned mesh, The option Fix Bone Hierarchy may help to fix this. Also, all bones have to be “bones”, not “groups” or “meshes”. 3ds Max Character Studio uses meshes as bones, so it is not supported by U3D export.
Fix Bone Hierarchy	Performs adjustments to the bone hierarchy when converting some scenes with skin and bones
Metadata	Embeds metadata in the .u3d file. The metadata is stored internally, in XML format, which increases the file size.