The Imagine export converter writes out the entire scene database as
triangular meshes along with all material definitions and all lights present
in the scene. The converter will also automatically convert all bitmaps
referenced in the originating scene to a 2D bitmap format supported by
Imagine.
When exporting to a file for use in Imagine version 1.3, face groups can be
output allowing texture maps to be restricted to only those faces within the
same group. This is useful when the original scene format allows textures to
be assigned at the polygon level. Imagine only supports textures at the
polygon level in conjunction with face groups.
When exporting files for version 1.0 or 1.1 or Imagine, if an object has more
than 32767 polygons, edges, or vertices then a complex algorithm (in this
export converter) will be invoked to split the object apart into multiple
pieces, each with less than 32767 polygons, edges, and vertices. The new
objects will be children of an empty node with the same name as the original
object. Please take note that the new sub-objects created will not share
vertices along the seams, and thus smoothing will not occur between the new
sub-objects within Imagine. For example, if a sphere which consists of 120000
polygons is exported to a 3D Studio file then the sphere will be broken up
into multiple sub-objects; the seam between the two sub-objects will not
appear to be smooth when rendered within Imagine because of this smoothing
limitation. Files for Imagine 1.3 do not suffer from this size limitation on
objects.
Dialog Box Options
The following information explains the various options on the dialog box:
File Version
The file exported can conform to the format used by Imagine versions
1.0, 1.1, or 1.3.
Auto Bitmap Conversion
Auto-Convert Bitmap Files to Another Format
If this option is enabled (checkmarked) then all 2d bitmap textures which are
currently defined and referenced by the internal database scene will be
automatically tagged then converted to a new user-specified 2d bitmap file
format. For example, if you are converting a Lightwave scene to Imagine, and
the Lightwave file references IFF bitmap files then this option can be
enabled so that the IFF images get converted to TIFF format automatically.
The converted bitmap files will be placed in the same output directory as the
converted .3ds file. If the texture(s) cannot be found in the location
specified by the pathname prepended to the texture filename, then the export
converter will search for the texture(s) in all directories specified in the
'Default Search Path' and the 'Texture Bitmaps Search Path' file search paths
(these can be modified by choosing the 'Preferences/Configure File Search
Paths' menu item.
Bitmap Depth (Bits/Pixel): 2, 4, 8, 24
These radio buttons determine the number of bits/pixel to write out to the
new 2d bitmap file. The default is 24 bits. A color quantization algorithm
will be used for the 2, 4 and 8 bits/pixel output formats.
Dimensions: X = #, Y = #
These two drop-down list boxes determine the X and Y resolution for the
converted bitmap file(s):
No Change = Do not change the X or Y size
Closest = Use the next highest power-of-2 size
2, 4, 8, ... 256, 512 = Choose a specific size for the X or Y dimension
Confirm Potential Bitmap File Overwrites
If this checkbox is enabled (checkmarked) then the bitmap converter will
confirm any potential overwrites of existing bitmap files on disk which
have the same filename and extension as the one being written. If this option
is disabled then no confirmation will be made.
Convert all Bitmap File References To...
If the 'Auto-Convert Bitmap Files to Another Format' option is disabled then
this option can be enabled. Rather than convert referenced bitmap images to
another file format this option (when enabled) simply changes all the file
extensions on bitmap files to a specific type. For example, if set to "TIFF"
then all bitmap filenames exported to the Imagine file will be changed so
that their file extensions end in ".tif". This is a useful option is you
already have all of the referenced texture maps converted to the desired file
format (either from a previous invocation of this export converter or by
using a batch bitmap conversion program). If this option and the 'Auto-
Convert Bitmap Files to Another Format' option is turned off then the
filename extension will remain unmodified.
Output Enables
The check boxes inside the 'Output Enables' section control what type
of data will be output to the Imagine file:
Face Groups
If this option is enabled (checkmarked) then face group data will be exported
for polygons within an object which use the same surface definition. This
allows any texture maps on an object to be restricted to only the polygons
within the same group.
Lights
If this option is enabled (checkmarked) then any ambient, point, directional
or spot light sources will be output to the IOB file.
Material
If this option is enabled (checkmarked) then all materials (surfaces)
referenced by the current 3d database will be output to the IOB file.
Bitmap References
If this option is enabled (checkmarked) then texture bitmap references will
be output to the IOB file by any material that references any bitmap file (2d
texture maps).
Limitations
Cameras are not exported. The file format used for .iob files does not
support cameras.
Directional light sources are exported as cylindrical lights for file
versions 1.0 and v1.1. They are output as proper parallel ray light sources
with no shape for file version 1.3.
File versions 1.0 and 1.1 do not support objects with over 32k polygons,
edges, or vertices. Such objects will be split into smaller pieces when
output. Version 1.3 files do not have this limitation.
Due to a limitation of the file format used for .iob files, vertex
coordinates cannot contain values outside of the range from -32768.0 to
32767.0.
The texture modulation types supported by Imagine that can be exported are
diffuse colour, reflectivity, bump mapping, ambient colour (1.3 only),
specular colour (1.3 only), and face opacity (1.3 only). Any textures which
modulate face opacity will be exported as Imagine stencils which modulate
diffuse colour with chroma-keyed transparency.
Imagine does not support UV texture coordinates. It does support planar,
cylindrical, and spherical texture projections.
Planar projection only extend from the projections origin along the
length of the y-axis so these projections may need their local y-axis scaled
from within Imagine if the texture does not extend far enough as exported.
Spherical and cylindrical projections in Imagine do not support repeating the
texture map around the circumference of the projection. However, cylindrical
projects to allow repeating along the projection's z-axis.
Box projections are output as planar projections. In many cases the
projection will have to be adjusted from within Imagine.
If face grouping is enabled (only valid for version 1.3 file format) then
polygons are grouped by surface definition. This allows a limited simulation
of texturing on a polygon level, something that Imagine only allows via face
grouping. The limitation on this texturing is that since the internal
intermediate database only supports one texture projection per entire object
and Imagine does not support UV texture coordinates, then all textures on an
object will share the same projection. Projections for each texture map on
an object can be altered from within Imagine if necessary.
Imagine does not support assigning specular material attributes at the
polygon level, but does support it at the object level. Therefore the
specular attributes for Imagine objects only come from whatever material is
assigned at the object level.
Dialog Box Options