Currently I am modelling a rectangularspace with wind tower, the wind tower
extends 3 meters above the roof of the space with openings from the four
sides. The wind tower dimension is 2X2 meters.It does not have glazing I
am using special illum on the opening of it. The material inside the
windtower is non reflective, made with stucco, reflectivity of almost 85%
I wanted to know what would be the best ambient bounces to use while
simulating it since two sincers wher placed in side the space, one sensor
is placed directly under the windtower, and the other one is at the center
of the space.

Thank you,

Usually it helps to draw a section of the room.

Indirect component from sky - 1 bounce.
Interreflection in the tower (I guess you mean no SPECULAR reflection, cannot ?magine non-reflective surfaces there) - 1 or two more bounces.
Now you want to consider that even the room's ceiling gets some light from the tower, which is reflected by walls and floor (are there any other openings to illuminate the room?), so add one or two.

All in all I get between 3 and 5 bounces. If you use rad and a rif file, note that the quality setting influences the ambient bounces calculated.

BTW, if you use an illum surface, you will need far less. How important is it to get "nice" pictures in your case?

CU Lars.


If you are using Radiance under UNIX, then a script to test for convergence may help. Have a look at the example in Section 6.4 of the Radiance book.



Radiance 2006 Scientific Workshop, 13-14 (Wed-Thu) September, De Montfort University, Leicester, UK.


Dr. John Mardaljevic
Senior Research Fellow
Institute of Energy and Sustainable Development
De Montfort University
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