Virtual Lab - Java3D Specs

Source: com.sun.j3d.loaders.objectfile.ObjectFile

The ObjectFile class implements the Loader interface for the Wavefront .obj file format, a standard 3D object file format created for use with Wavefront's Advanced Visualizer (tm) and available for purchase from Viewpoint DataLabs, as well as other 3D model companies. Object Files are text based files supporting both polygonal and free-form geometry (curves and surfaces). The Java 3D .obj file loader supports a subset of the file format, but it is enough to load almost all commonly available Object Files. Free-form geometry is not supported.

The Object File tokens currently supported by this loader are:

v float float float

A single vertex's geometric position in space. The first vertex listed in the file has index 1, and subsequent vertices are numbered sequentially.

vn float float float

A normal. The first normal in the file is index 1, and subsequent normals are numbered sequentially.

vt float float

A texture coordinate. The first texture coordinate in the file is index 1, and subsequent normals are numbered sequentially.

f int int int . . .

or

f int/int int/int int/int . . .

or

f int/int/int int/int/int int/int/int . . .

A polygonal face. The numbers are indexes into the arrays of vertex positions, texture coordinates, and normals respectively. There is no maximum number of vertices that a single polygon may contain. The .obj file specification says that each face must be flat and convex, but if the TRIANGULATE flag is sent to the ObjectFile constructor, each face will be triangulated by the Java 3D Triangulator, and therefore may be concave. A number may be omitted if, for example, texture coordinates are not being defined in the model. Numbers are normally positive indexes, but may also be negative. An index of -1 means the last member added to the respective array, -2 is the one before that, and so on.

g name

Faces defined after this token will be added to the named group. These geometry groups are returned as separated Shape3D objects attached to the parent SceneGroup. Each named Shape3D will also be in the Hashtable returned by Scene.getNamedObjects(). It is legal to add faces to a group, switch to another group, and then add more faces to the original group by reissuing the same name with the g token. If faces are added to the model before the g token is seen, the faces are put into the default group called "default."

s int

or

s off

If the vn token is not used in the file to specify vertex normals for the model, this token may be used to put faces into groups for normal calculation ("smoothing groups") in the same manner as the 'g' token is used to group faces geometrically. Faces in the same smoothing group will have their normals calculated as if they are part of the same smooth surface. To do this, we use the Java 3D NormalGenerator utility with the creaseAngle parameter set to PI (180 degrees - smooth shading, no creases) or to whatever the user has set the creaseAngle. Faces in group 0 or 'off' use a creaseAngle of zero, meaning there is no smoothing (the normal of the face is used at all vertices giving the surface a faceted look; there will be a crease, or "Hard Edge," between each face in group zero). There is also an implied hard edge between each smoothing group, where they meet each other.

If neither the vn nor the s token is used in the file, then normals are calculated using the creaseAngle set in the contructor. Normals are calculated on each geometry group separately, meaning there will be a hard edge between each geometry group.

usemtl name

The current (and subsequent) geometry groups (specified with the 'g' token) have applied to them the named material property. The following set of material properties are available by default:

			 amber           amber_trans       aqua            aqua_filter
			 archwhite       archwhite2        bflesh          black
			 blondhair       blue_pure         bluegrey        bluetint
			 blugrn          blutan            bluteal         bone
			 bone1           bone2             brass           brnhair
			 bronze          brown             brownlips       brownskn
			 brzskin         chappie           charcoal        deepgreen
			 default         dkblue            dkblue_pure     dkbrown
			 dkdkgrey        dkgreen           dkgrey          dkorange
			 dkpurple        dkred             dkteal          emerald
			 fgreen          flaqua            flblack         flblonde
			 flblue_pure     flbrown           fldkblue_pure   fldkdkgrey
			 fldkgreen       fldkgreen2        fldkgrey        fldkolivegreen
			 fldkpurple      fldkred           flesh           fleshtransparent
			 flgrey          fllime            flltbrown       flltgrey
			 flltolivegreen  flmintgreen       flmustard       florange
			 flpinegreen     flpurple          flred           fltan
			 flwhite         flwhite1          flyellow        glass
			 glassblutint    glasstransparent  gold            green
			 greenskn        grey              hair            iris
			 jetflame        lavendar          lcdgreen        lighttan
			 lighttan2       lighttan3         lighttannew     lightyellow
			 lime            lips              ltbrown         ltgrey
			 meh             metal             mintgrn         muscle
			 navy_blue       offwhite.cool     offwhite.warm   olivegreen
			 orange          pale_green        pale_pink       pale_yellow
			 peach           periwinkle        pink            pinktan
			 plasma          purple            red             redbrick
			 redbrown        redorange         redwood         rubber
			 ruby            sand_stone        sapphire        shadow
			 ship2           silver            skin            sky_blue
			 smoked_glass    tan               taupe           teeth
			 violet          white             yellow          yellow_green
			 yellowbrt       yelloworng
		   
mtllib filename

Load material properties from the named file. Materials with the same name as the predefined materials above will override the default value. Any directory path information in (filename) is ignored. The .mtl files are assumed to be in the same directory as the .obj file. If they are in a different directory, use Loader.setBasePath() (or Loader.setBaseUrl() ). The format of the material properties files are as follows:

newmtl name

Start the definition of a new named material property.

Ka float float float

Ambient color.

Kd float float float

Diffuse color.

Ks float float float

Specular color.

illum (0, 1, or 2)

0 to disable lighting, 1 for ambient & diffuse only (specular color set to black), 2 for full lighting.

Ns float

Shininess (clamped to 1.0 - 128.0).

map_Kd filename

Texture map. Supports .rgb, .rgba, .int, .inta, .sgi, and .bw files in addition to those supported by TextureLoader.

d transparency

The transparency value of this texture (clamped to 0.0 - 1.0).