Download V6.60 Release Notes

RELEASE OF V6.60 TNT PRODUCTS
enhancement tools are available to allow you to refine the image. The sample landscape files that have been prepared by MicroImages, which were described in an earlier
section, illustrate some of the range of possibilities for creating dynamic, data-rich textures for 3D simulations.
Relating Texture and Terrain.
Once you have the candidate terrain and texture layers loaded and refined, you can determine the orientation and extents of the output landscape layers. Push-buttons on the
Landscape Builder window allow you to automatically orient and clip the objects to the
selected terrain object or to the active layer in the View of the texture layers (set in the
Landscape Builder Layer Controls window). You can also use standard dialogs to reorient all objects to any map projection, with the results shown automatically in the View.
You can use the Output Extents graphic tool to resize the extents box to include exactly
the desired area in the simulation.
Determine the relative sizes of output texture and terrain objects by setting the Texture/Terrain Raster Size Ratio (1, 2, 4, 8, 16, 32, or 64). You can also specify which cell
size should be held constant when the ratio setting is changed and the method used to
resample cell values to create the output terrain object (Nearest Neighbor, Bilinear Interpolation, or Cubic Convolution). Currently the texture raster is created using only
Nearest Neighbor resampling, but future versions will allow bilinear resampling as well.
This change will allow you to hold the terrain cell size constant and use interpolation to
resample the texture to a much smaller cell size, producing a smoother texture image.
You can manually edit the output line and column dimensions and cell sizes, but values
you enter are automatically adjusted to maintain the selected ratio and to ensure that
the output texture and terrain objects have dimensions suitable for the simulator. Each
dimension of the texture raster (in cells) is maintained as a power of 2 multiple of 256
(for example, 256, 512, 1024, 2048). This restriction is related to the special texturetiling scheme used in TNTsim3D’s texture server, which uses tiles that are 256 by 256
cells in size. The dimensions of the terrain raster are computed as the texture dimension divided by the selected size ratio, plus 1 cell. For example, with output texture dimensions of 1024 by 4096 and a texture/terrain ratio of 4, the terrain raster will be assigned dimensions of 257 by 1025. You can also choose the color-depth of the output
texture image (24-bit, 16-bit, or 8-bit with color palette).
Minimizing File Size.
When building a simulation, keep in mind that your choices for cell sizes, texture/terrain
size ratio, and raster sizes will impact the appearance of the simulation and the performance of the simulator. A highly-detailed terrain layer is not required for a realisticlooking simulation, so consider using a relatively high texture/terrain size ratio and holding the texture cell size constant (producing a smaller, coarser terrain raster). This
strategy will maximize the detail of your texture layer while maintaining smaller sizes for
both objects. Using a high ratio and holding the terrain cell size constant introduces no
additional detail in the texture layer, but may increase the object sizes enough to impact
the performance of the simulator, introducing pauses in the moving image at higher
flight speeds.
Modifications since V6.60 CDs.
Since the CDs were mastered the Landscape Builder has been modified in several ways
to better handle “no data” areas in terrain objects and to correct minor errors.
MICROIMAGES MEMO
60
21 DECEMBER 2001