The 'Apple QuickDraw 3D Metafile' format (3DMF) has been a popular 3d data file
format used on the Apple Macintosh platform, and somewhat popular on the Windows
platform. Most Macintosh-based 3d applications can read and write the 3DMF format.
This 3DMF export file converter is a complete implementation of the 3DMF file
format specification. The main features include:
Proper translation of all forms of geometry into the 3DMF 'Mesh' primitive, complete with support for
the 'VertexSetAttributeList', 'FaceSetAttributeList' and 'MeshCorners' sub-objects.
Complete support for n-sided polygons with recursive holes and islands.
Object hierarchy support by embedding mesh data within 'Group' nodes.
All vertex attributes are supported, including: normals, (u,v) texture coordinates, (U,V) tangent
vectors and diffuse color. All mesh output has been optimized to produce the smallest file size according
to which vertex attributes are present.
NURB patches output as the 3DMF 'NURBPatch' primitive, or they are optionally output as polygons.
Embedding of bitmap texture images within the 3DMF file. If a bitmap image is used more than once
for multiple objects then only one copy is ever used within the file ('Reference()' keywords are used to
instantiate the image).
If more than one texture map is assigned to a single object then that object will be exploded into
multiple separate meshes, each of which is assigned a single texture map (this is a complex
operation!).
Texture scale, offset and wrap-arounds (Clamp/Wrap flags) are properly
handled and output. This will allow for perfect translation of texture mapped
surfaces!
Dialog Box Options
The following information explains the various options on the dialog box:
Export Options
File Type = ASCII, Binary
If the radio button is set to Binary then the 3DMF file will be written in the binary file format. If set to
ASCII then the 3DMF file will be written in the ASCII file format.
File Version = 1
This selects the desired 3DMF output file format. At the present time this can only be set to 1.
Embed Texture Images Within File
If this option is enabled (checkmarked) then any texture images referenced by the 3DMF data will be
embedded directly within the file. The converter can convert and embed the following file formats (and all
of their variations): BMP, FLIC, GIF, CEL (Autodesk), JPEG, Targa and TIFF. If a texture image is
referenced more than once then the 3DMF output converter will use the 'Reference()' statement to
reference the previously output bitmap rather than create another varbatim copy of the bitmap data inside
the file.
Add Three Default Directional Light Sources
If this option is enabled (checkmarked) then 3 directional light sources will be inserted into the 3DMF file:
one to the upper-left, one to the upper-right and one in the middle-back. Without these light sources the
scene may look very dark when viewed in the destination program. If this option is disabled then no
default light sources will be output but rather only the lights currently defined in the internal database will
be output to the 3DMF file.
Output All Polygons As Triangles
If this option is enabled (checkmarked) then all polygons which have 4 or more sides will be converted to
triangles prior to output. Concave polygons and polygons with holes will be properly triangulated.
Reverse Orientation of all Polygons
If this option is enabled (checkmarked) then the orientation of all polygons will be reversed (this will
effectively swap the orientation of the polygons geometric normals).
Output NURB Patches as Polygons
If this option is enabled (checkmarked) then all NURB patches will be output to the 3DMF file as
polygons. If disabled then all NURB patches will be output as 'NURBPatch' primitives.
Output Comments to 3DMF File
If this option is enabled (checkmarked) then comments will be embedded within the ASCII 3DMF file.
These comments annotate various aspects of the 3DMF data. If this option is disabled then no comments
will be output to the file which will make it smaller and faster to load.
Line Terminator Type
This common option selects which line terminator is to be used for the ASCII
output file:
Files destined for DOS/PC machines should use CR/LF,
Files for UNIX machines should use LF, and
Files for Macintosh machines should use CR.
The default is specific to which machine this converter is presently
running on: CRLF for DOS/PC, LF for UNIX and CR for Macintosh. This option
normally does not have to be specified unless you will be using the exported
ASCII file on a different type of computer.
Shading Related Modifiers
Multiply shading coefficients in the Colors
Most 3d rendering problems use a shading model based on a RGB color and a series of shading
coefficients. For example, a diffuse coefficient value of 0.5 would cause the current diffuse
material color to be scaled by a value of 0.5 during the shading calculations. These coefficients
are imported from 3D data files such as those written by Lightwave, NuGraf and trueSpace.
However, QuickDraw 3D does not have any notion of these shading coefficients but rather
requires these values to be directly multiplied into the ambient and diffuse material colors.
If this option is enabled then the shading coefficients defined within the internal 3d database will
be multiplied into the colors before they are output to the 3DMF file - in some cases this may
make the exported data look better (less ambient in most cases). If the option is disabled (the
default) then the coefficients are ignored and only the raw ambient and diffuse colors are output
to the 3DMF file which may produce satisfactory results in the destination 3DMF viewer program.
Basically, if the final scene looks flat or too ambient (even with 1 or 2 light sources in the scene)
then try enabling this option.
Override 'AmbientCoefficient Values With [value]
The AmbientCoefficient keyword within a 3DMF file controls the amount of ambient light that is
added to a materials color. If this value is set to 0 then no ambient light is added and if the value
is set to 1.0 then 100% of the ambient light is added. Many files exported to 3DMF have this
value set incorrectly causing objects that appear either too dark or too ambient. To overcome this
problem, enable (checkmark) this option and change the type-in numeric value to the desired
AmbientCoefficient value - this will cause all ambient coefficient values in the exported file to
take on the value specified in the type-in box.
Override SpecularControl Values With [value]
The SpecularControl keyword within a 3DMF file controls the size of the specular highlight
seen on a shiny object. If this value is set to 0 then no highlight is seen. Values from 1 to 300 will
make the highlight becoming increasingly narrower, and hence, the object(s) will appear to
become more shiny. If this checkbox is enabled (checkmarked) then the numeric value shown in
the type-in will be used throughout the 3DMF file for the SpecularControl value of each material -
this allows you to modify the specular highlight size to a specific value for material definition in
the file.
Output Enables
The check boxes inside the Output Enables section control what type
of data will be output to the 3DMF file:
Vertex Normals
If this option is enabled (checkmarked) then any normals that are assigned to polygon vertices
will be output to the 3DMF file.
Vertex Colors
If this option is enabled (checkmarked) then any colors that are assigned to polygon vertices will
be output to the 3DMF file.
Vertex (u,v) Textures
If this option is enabled (checkmarked) then any (u,v) texture coordinates that are assigned to
polygon vertices will be output to the 3DMF file.
Vertex (U,V) Tangents
If this option is enabled (checkmarked) then any (U,V) tangent vectors that are assigned to
polygon vertices will be output to the 3DMF file. Tangent vectors are typically needed to perform
bump mapping.
Mesh Data
If this option is enabled (checkmarked) then all geometry currently defined in the 3d database will
be output to the 3DMF file.
Cameras
If this option is enabled (checkmarked) then the parameters of the current default camera will be
output to the 3DMF file. Both perspective and orthographics cameras are accomodated.
Lights
If this option is enabled (checkmarked) then any ambient, point, directional or spot light sources
will be output to the 3DMF file.
Polygon Materials
If this option is enabled (checkmarked) then any material attributes assigned to individual
polygons will be output to the 3DMF file using the 'FaceSetAttributeList' structure. This option
will also allow default material attributes to be assigned to a mesh.
Dialog Box Options