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LIGHTING DESIGN - Radiance Materials |
Using more Complex Radiance Materials
This is a short tutorial on how to use more complex RADIANCE materials from
within ECOTECT. You should have already done the Exporting
to Radiance tutorial to make sure that RADIANCE is set-up properly on your
machine and that you can successfully export a scene file from your model.
- Open the Radiance-Materials.eco
file from the Tutorial Files folder in your main ECOTECT Install directory.
There are three zones in this model, one called Room, one called Box and the
default Outside zone. It is a simple room with a camera and a large box box
in the middle. Essentially the box is the object whose materials we are going
to change. It should already be grouped so you only need to click one object
to select them all.
Rendering the Base Model
- First off, export the model to Radiance to see what material the box
is currently assigned.
The box should be assigned the material 'LightBlue'. You can export to Radiance
using either the Export Manager panel to the right of the
main application window or the Export... item in the File
menu.
Either way you should be prompted for a filename to save the scene files -
simply choose somewhere like C:\Temp\Test.rif, remebering the problems Radiance
sometimes has with long file names.
You should then see the see the Radiance Export dialog, in which you should
ensure that an Overcast Sky is selected and that the action is set to Final
Render, as shown below.
This should produce an image similar to the following:
Defining a More Complex Material
- Make sure you have set the Default Export Material Directory in the Preferences
Dialog.
When ECOTECT exports any file, it can be set to look in both the local model
directory and a global shared directory for matching material files. Simply
select the User Preferences item in the File
menu and ensure that you have the item highlighted below set to the Materials
folder in your main ECOTECT install directory.
You can create a your own export materials directory and redirect ECOTECT
to there if you work with a lot of your own materials, however this tutorial
uses the 'WoodGrain.rad' and 'BrickRough.rad' files which should already be
installed in the default Materials folder. If you have changed this directory,
simply copy these two files to the area you now use.
- Select the box and assign it the 'BrickRough' material.
As mentioned previously, the box is grouped so you should only need to click
on one object to select the whole box. Once it is selected, open the Material
Assignments control panel on the right hand side of the main application
window (the tab with the checkered material swab) and select the BrickRough
material, as shown below.
- Once again export the model to Radiance as you did in the very first
step, this time ensuring that the 'Check for Material.rad files' item is checked.
This item can be found in the Radiance Export dialog in the
Material Definition group.
Checking this option instructs ECOTECT to check in either the same directory
as the ECOTECT model or the Export Materials directory for any files with
the same name as any materials in the model. We have assigned the box 'BrickRough',
so ECOTECT will look for a file called 'BrickRough.rad'. It understands that
.rad is the prefix for Radiance files whereas if you were exporting to VRML
it would look for 'BrickRough.wrl', etc.
You should end up with an image similar to the following:
If you were to examine the Radiance scene file created by ECOTECT, you would
find that it has substituted the following for the definition of the BrickRough
material:
# <== [C:\Program Files\Square One\Materials\BrickRough.rad]
void texfunc BrickRough_m1
4 Xp Yp Zp brick1.cal
0
6 .020 .040 .230 .115 -0.7 0.7
BrickRough_m1 texfunc BrickRough_m2
6 xwrink ywrink zwrink wrinkle.cal -s 0.1
0
3 0.05 0.05 0.15
BrickRough_m2 plastic BrickRough
0
0
5 0.150 .075 .012 0 0.2
# ==>
It has simply inserted the contents of the 'BrickRough.rad' file diectly into
the scene file. You will notice that the material definition ends up defining
it as 'BrickRough'. Thus, even though the file system will recognise a material
called 'brickrough' as matching 'BrickRough', the Radiance render will fail
as its material definitions are case-sensitive.
The code inside the file contains relatively straighforward Radiance instructions.
For more information on what they mean if you wish to edit and customise them,
see the file RadianceReferenceManual.pdf in the manuals folder
in your Radiance directory.
Experimenting with Different Values
- As a short exercise to reiterate what we have done, try assigning the
box as WoodGrain.
Perform the same steps as above, this time choosing the 'WoodGrain' material,
just to show how easy it is once you have a library of materials. You should
end up with an image similar to the following:
- If you are feeling experimental, save the ECOTECT model into your
own home directory (if you are on a lab or office machine) and copy the WoodGrain.rad
file to the same directory as you saved the model.
- Open the local copy of the 'WoodGrain.rad' file in a text editor
such as NotePad.
The file should look like the following. The numbers that you can change without
having to worry about anything are highlighted in red. For example, the number
after the -s in the second line is simply the scale of the randomised dirt
function. The numbers at the very bottom represent the red, green and blue
colours of the base material colour followed by a specularity and roughness
value.
void brightfunc WoodGrain_b1
4 dirt dirt.cal -s 0.008
0
1 0.15
WoodGrain_b1 brightfunc WoodGrain_b2
4 zgrain woodpat.cal -s 0.016
0
1 0.55
WoodGrain_b2 texfunc WoodGrain_tex
6 xgrain_dx ygrain_dx zgrain_dx woodtex.cal -s 0.01
0
1 0.075
WoodGrain_tex plastic WoodGrain
0
0
5 0.35 0.3 0.15 0.005 0.025
The aim is simply to get a feel for how easy (or obscure depending on your
perspective) it is to achieve different effects with the different parameters.
Don't worry if you mess up this file as you can always copy the original back
over the top of it if you need to start over.
