reference materialDome Radiosity in Lightwave
by: Jonathan Adams


There are other tutorials about using spinning lights to create a radiosity effect in Lightwave. This effect uses motion blur and lights which rotate around a null. The shadow and lighting is then blurred with previous frames to create a ambient light effect. This tutorial will show you how to render your objects using a dome which acts as the light source. Thus light is produced all around your object giving the true ambient light effect for real life renders.

This method of rendering can take a while and is really only good for still images. If you want your object to look like its tangible then this the way to go.

 

Step 1: Pick your model and create the Dome

This step can be done in the original object file or done in its own object file. If you were to create the dome as its own object you could then import it into Layout with any object you want. You only have to worry about the size of the dome and the size of the object. You don't want a dome which is to small or you object may be sticking out the sides. In this tutorial we will create the dome in the same object file as our object in order to get the correct size and for simplicity. I am using a simple table object but you may use whatever you like.

 

Step 2: Creating the Dome

First create a the base of the dome using the ball tool in the Top View. Make sure that you make it big enough to fit around the object with plenty of space. You can see my able object in the center.
Then you want to create the height of the dome in the Back View. Be sure to create the ball so the middle axis acts at the ground to your object. The same idea applies. Make sure it is large enough.
Then select the bottom half polygons of the ball and delete them.
Select only the bottom row of points and create a polygon using the hotkey "p"
Look to see if the newly created polygon is facing the correct direction and change it's surface name to "Floor" using the hotkey "q"
Now select the other polygons in the dome (not the floor), flip them using the key "f" and change their surface name to "Wall" using the hotkey "q"
Now you are ready to save your object and head to Layout.

 

Step 3: Setting up the object in Layout

Import your new object file into Layout and move your camera into the dome and as close to the object as you want. Frame up your scene and create the settings as follows for your surfaces and camera.

While using the camera, under properties change the anti-alliecing to low. This will create a much cleaner image.
You can set up your floor how ever you would like. I have chosen a dark gray color and a diffuse of 90 percent. You can experiment with reflection and other settings as you get to know this set up.
You may use any color you like, although which seems to give the best results. In order for your walls act as a light source you will need to turn on Luminosity. I have chosen 100 percent for this tutorial. The higher the number the more light and visa versa.

 

Step 4: Setting up radiosity

You must use radiosity to render your scene in order for the walls to act as a light source. There are different types of radiosity in Lightwave, I have chosen to work with the Interpolated settings and Monte Carlo. I have provided test images for each as well as times for render and settings.

 

First you will need to set up your render options. For the results that I will picture, these are the settings used. You must use ray trace shadows in order to get shadows, if you are using reflections as well you will need to turn those on also.

I have also turned off the default light in the scene by settings it's out put to 0 percent. You can used lights in the scene to create strong shadows, however the setting for your dome and colors may need to change.

 

Under the Global Illumination panel (In light properties) this is the default set up when you enable Radiosity. You will want to turn on Shading noise reduction and lower your ambient intensity to 5 percent or lower, if it is not already.

 

Image using above settings and low AA took 5 mins 49 sec.

 

 

This is the default settings for enabling the Interpolated type of radiosity. There are several more setting which you can play with now. I will only give examples of changing the Rays Per Evaluation (RPE), however you can save some render time by changing the tolerance to a low number like .02.

 
Using the above settings and low AA to 5 mins 40 sec.
Using Interpolated Radiosity and low AA. Changing the RPE to 6x18 took 12 mins 26 sec.
Using Interpolated Radiosity and low AA. Changing the RPE to 3x9 took 3 mins 24 sec.
 

Conclusion:

When choosing the method of radiosity to use, I find very subtle differences in between each test. Using the 3x9 RPE gave slight patchwork detail in the floor, however I see no difference in between the 6x18 and 4x12. A change might be seen when using a more complex model. The render times very by several minutes between the different RPE. I feel like using 6x18 RPE might be over kill for this scene, only leading to excess render time. I find my self using dome radiosity a lot in my still renders and I hope this tutorial helps you enjoy the realistic lighting as well.