2012

Table Of Contents
the AutoCAD 2008 format. However, there are some fidelity issues when saving
back to previous versions of AutoCAD.
Procedural maps Checker, Noise, Speckle, Tiles, and Waves are not available
in AutoCAD 2007 (and previous releases.) They do not appear when an
AutoCAD 2008 drawing is opened in AutoCAD 2007. Marble and Wood
are available but the material mayshow some variation.
The behavior of the Opacity map channel under the Realistic material type
has been corrected in AutoCAD 2008. In AutoCAD 2008, the Opacity map
channel behaves like a transparency map, where white is transparent and
black is opaque (this was how it behaved prior to AutoCAD 2007). In
AutoCAD 2007, white represented opaque areas and black represented
transparent areas.
The spherical map rotation is different in AutoCAD 2008. When you open
a drawing prior to AutoCAD 2008, the seam for the map is towards the +Y
axis. In AutoCAD 2008, it is towards the +X axis.
Lighting in Previous Releases
AutoCAD 2008 provides two options for lighting: standard (generic) lighting
and photometric lighting. Previous versions offered only standard (generic)
lighting. There is no explicit conversion required for lights from AutoCAD
2007 to AutoCAD 2008. Drawings from AutoCAD 2007 open by default in
AutoCAD 2008 in the standard (generic) lighting workflow. The additional
photometric properties available in AutoCAD 2008 are available as soon as
the photometric lighting workflow is enabled in the drawing.
There is a conversion process required for drawings with lighting prior to
AutoCAD 2007. You can use a system variable, 3DVCONVERSTIONMODE,
to automatically convert drawings with lighting from previous versions to the
AutoCAD 2007 and AutoCAD 2008 lighting format. 3DCONVERSIONMODE
has three settings. If set to 0, no conversion takes place. If set to 1, the default
value, the conversion takes place automatically. If set to 2, then you are
prompted when lights need to be converted and will have the option to convert
or not to convert.
Other lighting fidelity issues include
Lights in blocks. Lights in blocks created in AutoCAD 2008 do not always
display in AutoCAD 2007.
Texture illumination. In AutoCAD 2007 (and earlier releases), you cant
add lighting to textures. In AutoCAD 2008, you can.
1958 | Chapter 37 Work with Data in Other Formats