LIGHTING DESIGN - Exporting to Radiance
Interfacing with Radiance
In this tutorial you will learn how to export a file to the RADIANCE
Synthetic Imaging software and generate realistic lighting levels.
RADIANCE is not installed with ECOTECT, however it is a freely available
public-domain application from Lawrence
Berkeley Laboratories. You will need to have either downloaded and
installed the free Desktop Radiance software from the Lawrence
Berkeley site or purchased the ADELINE package to complete this
- Open Classroom.eco from
the Tutorial Files directory located in your main ECOTECT Install directory.
There only two zones in this model, one called Classroom and the default Outside
Creating a Camera View
- We first want to set up a camera in order to view the interior
of the room.
To create a camera, click the Camera button
in the left-hand side toolbar. To position the base point of the
camera, use the Control key to move the cursor up and down in
the Z axis and then drag it into position. Be careful not to position
it exactly on or in any of the wall, floor or ceiling planes or you
will end up looking directly at a flat featureless surface. Once you
position the first node, ECOTECT will prompt for a second. Simply drag
the 'look at' node to the other end of the enclosure as shown.
It does not matter if the second node sits on a plane or is coincident
with any particular point as it serves only to provide a view direction.
If you need to reposition the camera after placing the second node,
simply double-click on the camera object and select either node to move
it. The view direction is always indicated by the 'pointy' end (the
one with the arrow).
Before moving on and calculating light levels, it is important to make sure
that the analysis grid is set appropriately. If the grid is altered in any
way after calculations have been performed, the calculated values will be
lost. See the Lighting Introduction
tutorial if you need more information.
Setting Camera Properties
- To set the properties of the camera, make sure it is selected
and click the Material Assignments Tab icon
to display its assigned material.
The Materials Tab is located on the right hand side of the main ECOTECT
application window. There is only one CAMERA material in this model
so it is automatically assigned.
- The next step is to modify the field of view of the camera. To
do this simply double-click on the 'External_Camera' entry in the materials
You should now see a dialog box like the one below - change the horizontal
and vertical angles to 90 and 60 degrees respectively as shown below
and click the OK button.
The camera's pyramid shape should update, as shown below.
Exporting to RADIANCE
Once you have created a camera, you are ready to export to Radiance.
- To generate a Radiance image, select the Export... item in the
File menu and change the file type to Radiance Scene File.
Basically Radiance doesn't seem to handle long file names at all well.
Some of its components do, but things such as PFILT and PCOMB don't.
Always save your Radiance scene files in a very simple directory structure
(such as C:\temp\rad\run1 or something). Never use spaces in the names
or names greater than 8 characters long. Sometimes they'll work, most
of the time not.
Once you select a file name the following dialog box will be displayed:
- Ensure you change all the settings to match those shown above and
then click the OK button.
You should now see a DOS Command Prompt appear and a whole range
of command line data display. Radiance should automatically run, which
may take a while. However, it should periodically display its calculation
status as it goes.
If you do not see DOS prompt it is likely that you did not select the
Save+Final Render option at the bottom of the dialog. If you
instead see a dialog box asking you to locate the Radiance Application
RAD.EXE, then this is simply the first time it has been run on your
machine and ECOTECT has been unable to find the Radiance directory in
all the usual places. Simply navigate to where you installed Radiance,
enter the bin directory and choose the RAD.EXE file. You should
then see the DOS Prompt.
If your DOS Prompt appears and then disappears almost immediately then
you are in trouble. We;ve tested and re-tested the Classroom.eco file
with Radiance, so you can be pretty certain its an installation issue.
You could try selecting the Save + Invoke RadTool option, then
set the Pause on Completion option in the Settings dialog
box to try to deduce when the problem might be, however you will probably
find the information you need in the Square
One forum as we get quite a few enquiries about setting up Radiance.
You can get quite comprehensive help on all the settings in this
dialog by clicking the Help... button.
Radiance is an excellent tool for highly accurate and quick lighting analysis,
however it can be a little temperamental and takes a bit of getting used to.
Whilst you can use ECOTECT to bypass much of the data entry and command line
issues with Radiance, however you should have a good read of the documentation
that comes with it if you wish to use it for more than simple visualisation.
- Once the calculation is complete you should see an image very
similar to the following pop up in WinImage.
As selected in the dialog box, this is an illuminance image, not a luminance
image. This means that it differs from a photographic image by showing
the amount of light falling on each surface as opposed to the amount
of light reflected off.
Generating Contour/False-colour Images
The real benefit of this is that you can generate false-colour and contoured
illumination maps directly from this image. To do this, simply select False-colour...
or Iso Contour... from the Analysis menu in WinImage.
This will display the following dialog:
Ensure you select Illuminance in the Quantity group and enter
a Maximum Value of 4000 Lux to set the scale. Selecting OK will
display the following image if you selected False-colour.
You can save this image as a Bitmap for inclusion in reports by simply selecting
Save As...from the File menu and setting the file type to Windows