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Title
The 3rd ISPRS Workshop on Dynamic and Multi-Dimensional GIS & the 10th Annual Conference of CPGIS on Geoinformatics
Author
Chen, Jun

ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS’’, Bangkok, May 23-25, 2001
412
multiplied by 2 H after each iteration (0<=H<=1). H is the
so-called self-similar variable. If let H=1, then the standard
deviation will be half of its original value after each
segmentation, which will lead the generated random function
to change significantly within a local area, so that rich in
texture. If this 2D random function is added to a curved surface,
then the texture on the surface is generated.
Besides, the chartlet of texture can be from a scanned
image or generated by a graphic package.
3.2 Problems of application of texture chartlet
Texture chartlet is used frequently In the whole simulation
process of lignigication. If all the texture chartlets used look
like the same in pattern but different in texture, then the
surface generated by these chartlets will be looked like a
wallpaper. In order to solve this problem, the material texture
needs to change randomly. Usually, large bitmap can be used,
however, to process it requires much computation time while to
store it needs more memory space. If different chartlets are
merged with certain proportion or particular noises are added
into chartlets, it will solve the problem effectively as well as
operationally. The following figures shown this result.
♦¿¿aU - * * • \ *u*
*4 . , ~r > » K +1»
Ti
J «U
J •
' * <-*#>• . -¿S .•*»«*
» » .'w.'
- • ». m * » *
^ > t*
Figure 3 emulational picture of dou-gong
Figure 4 emulational picture of
Dou-gong layer(planform)
£
W“
Figure 5 emulational picture of
4. Moving control techniques
All the graphs and images generated up to now are
stationary. The kernel of our project is dynamic virtual
simulation, so computer animation technique is a must.
Though many techniques of animation can be considered, the
key-frame based method is adopted here.
Figure 6 emulation picture of bell tower
dou-gong layer(upward view)
4.1 Key-frame based animation
The most popular computer animation technique is based
on key-frame technique. The core of this technique is to fix the
so-called key-frames, and then let 3DS MAX software system
to interpolate to generate those between key-frames. The B
spline function is used.