r. 
| light direction 
lecreases with 
the bright shi- 
pecular light is 
cted directly to 
urs when the 
:ction, otherwi- 
ble set of ligt 
t from ambient 
it and focuses 
linear and rec- 
general invisi- 
nt body. 
intensity , sha- 
e light colour. 
ht, a light sour- 
invers linar or 
invers square. Inverse linear shows better results when 
rendering. 
Environment and landscaping. The realistic environ- 
ment includes elements without part of the original 
AutoCAD drawing but should nevertheless contained 
inthe rendered image. These elements include back- 
ground and ground plane as well as three global 
lights, indirect light, fog and haze as well as depth 
cue. 
Is a modell shown in a perspective view a background 
should be imagined as an infinity globe around the 
model and the ground as an infinitiv surface underne- 
ath. 
On the globe colours, cloudes and bitmaps are projec- 
ted, wich can set the model into a realistic or even 
surrealistic surrounding. Ground can be covered by 
different materials. Fog and haze could simulate the 
effect of normal haze in the background up to real fog. 
Colours of haze correspond to background colour. 
Vegetation act as normal 3D objects, producing sha- 
dows and beeing reflected. 
FINAL RENDERING OF THE SAMPLE 
Samples of final rendering are given in the figures 2 
and 3. Recommended for a natural view is a perspec- 
tive transformation. Light marble is assigned to the 
walls, windows are defined as bright gray and strongly 
reflected metal in which the deep blue sky with the 
choosen cumulous clouds reflects. The light is the one 
in Luxembourg shining on August 29, 1995 at 12.30 
pm selected from the AccuRender light source me- 
nue. 
At the top of figure 2 one can observe some leaves of 
an oak tree. Renedering time for this image on a 
75MHz 486-computer with a resolution of 1280 x 1024 
pixels was approx. 57 minutes. 
Depending of the high amount to memory capacity 
figure 3 is shown in a resolution of 640x480 pixel only. 
Rendering time for this image was approx. 73 minutes. 
Size of the tif-format file is 1 Mbyte. 
In this image are som relfections to detect. In the 
window on the right one can observe reflections of the 
oak tree in front of the window. Reflections of the 
persons shadows are detectable as well. Background 
with cumulous clouds is shown as the mirrored image 
in the windows. The people are supplied from the 
library People for People which is delivered with pre- 
defined materials for the AccuRender program. 
Acknowledgements 
The data material, drawings and photos for this paper 
are kindly supplied from the surveying department of 
Kneip & Ass. in Luxembourg. Special thanks to Felix 
Peckels. 
References : 
Heiny, Loren, 1993. Advanced Graphics Programming 
Using C/C++.Wiley&Sons, Inc. 
Ray-trace Rendering and Animation in AutoCAD, 
Robert McNeel & Ass., 1995 
Pomaska, Günter, 1995. Bauaufnahme unter Berück- 
sichtigung der Anforderung von Informationssystemen, 
Schriftenreihe DVW 19/1995, Verlag Konrad Wittwer 
Pomaska, Günter, 1995. Aspects of todays photo- 
grammetry - the digital approach, CAE-Seminar, 
Fachhochschule Bielefeld 
477 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996