Create a radial light by clicking on the radial light icon in the Create Palette. From top view, increase the size of the light with the Resize tool so that you can see it well and to make it easier to manipulate into position inside your main sphere. Note: this will not increase the intensity of the light.

Place the light against the inside surface of the main sphere.

From camera view, check the position of the light in your scene. Using the top view and the left and right views, reposition the light where you want it in your scene, but keep it inside the main sphere, just against the inside surface.

To edit the intensity and color of the light, select the light and click the "E" next to the light's bounding box. This will bring up the light editor dialog box.

In this dialog, click the gray triangle under the preview window and check "render in scene". Experiment with the color and intensity of the light to create nova-like bursts as it reflects off the material of the main sphere.

Continue adding as many radial lights to your scene as you like.

If you find that your scene has become too bright, you have several remedies:

1. Open the Skylab in the Sky & Fog palette and check the disable sunlight option. This can considerably darken your scene, but still keep the individual novas visible.
2. You can simply move your sun out of the scene so that it isn't in the image, although its light will still influence the way your scene is developing.
3. You can begin putting in a few strategically placed NEGATIVE lights.

To use negative lights, create a radial light and assign it a different family color from the "nova" lights. This is important because you'll want to be able to tell the positive lights from the negative ones in your wireframe scene.

In the edit dialog for this light, click-drag to the left on the upper left window to bring the light intensity to a negative value. I've found that I often have to assign a relatively high negative value to the light in order for it to work effectively against all of the other lights in a scene.

You can change the color of your negative light here, too. Remember, this is a negative light, and whatever color you assign it, you will be subtracting amounts of that color from your scene. It takes a bit of practice to use negative lights effectively. But practice is half the fun!

Nebulae contain giant clouds of gas and dust, which obscure the light from the stars. To build these giant clouds, create another sphere, assign it a family color, and a cloud material from the Materials library of the Edit palette.

I chose "Lint" from the Clouds & Fogs menu, and brought the ambience, diffusion, and specularity all the way to zero in the materials editor. This makes the cloud a good, dense black...perfect for our nebula dust clouds.

Duplicate this sphere as many times as you see fit, and begin arranging these "dust cloud" spheres in the center of the main sphere, so that they obscure the nova lights behind them.

I've found that the best place to arrange these dust clouds is directly in front of the camera, so that the clouds appear to frame the image. However, I have arranged these clouds further away from the camera for some interesting, even surprising results. Again, experimentation is the key. Sometimes it takes only three or four dust cloud spheres to make the perfect effect.

By now your nebula should be taking shape quite nicely. This image shows the rendering of several radial "nova" lights against the inner surface of the main sphere; the subtraction of excess light using negative lights; the placement of dust cloud spheres close to the camera to give the illusion of dense gasses in my nebula.

The final image is the finished nebula scene. I added more radial lights for novas and larger stars, adjusting the negative lights to reduce the resulting excess brightness. Then I used Painter to add a few touches to give the image some added interest.

Experiment with the colors of the radial lights you used to make the novas. Change the sun color or the sun halo color to completely change the character of your image. Subtract color or light from the scene with negative lights, experimenting with negative color. Use the camera controls and the zoom tools to change the field of view or the camera angle. The possibilities are endless.

Above all, have fun!

Questions? Comments? You may e-mail me at Brettt@DTNSpeed.Net.