SECTION 2 - Modeling and Detail Editor

19] Halo around light sources: the glow effect.

There are several ways of doing this. The first method works under version 2.0 and 3.0, it takes the most work, but looks terrific if done correctly. The second method works under 2.0 and 3.0, and is easier, 3.0's version looks better due to the textures involved. The third method use Lens Flare and works only under 3.0.

You can refer to an easy example, a simple lightbulb. Think 2D for a bit, remember that the visible lightsource described is the type You'd see on film. What's a light look like? Well, there's a central disk of light that seems to be a constant brightness, the bulb itself. As You go further outward a secondary disk of light surrounds the central disk: this is the first halo, it is roughly twice twice the size of the central disk. It fades out rather quicky, it's, essentially, the part of the light that "burns" the film. Go further outward. There's a second halo, it's very dim and eventually fades out. This halo varies in size, but can usually be set to eight times the size of the original disk. This is the halo that is create when the light is dispersed by atmospheric conditions. So with that in mind:

Radial texture method:

Create a disk using Imagine's standard disk parameters.
Copy the disk and scale the new one by a factor of two.
Copy the larger disk and scale the new one by a factor of four. You should now have three disks of varying size.
Position the disks so that the smallest is in front of the middlesized. The middlesized is in front of the largest.
Make the smallest disk Bright with a Color of 255, 255, 255. Also, make it a lightsource.
Apply Radial textures to the middlesized and largest disks.
The middlesized disk should be Bright and have a Color of 150, 150, 255. The Radial texture should be set so that the disk's transparency is set to 0, 0, 0 at the center. Create a transition distance over the radius of the disk so that transparency is 255, 255, 255 at the disk's edge. You want the disk's color to fade as it moves toward the edge of the disk.
The larger disk should be Bright and have a Color of 255, 255, 255 and a Transparency of 170, 170, 170. Set the Radial texture so that the color fades to total transparency (255, 255, 255) at the disk's edge.
Transform the smallest disk's axis ONLY. Bring up the Transformation Requester, Rotate the Z axis 180 degree. Select the Transform Axis Only button and Perform. The disk's Y axis should be pointing exactly opposite the other disks' Y axis.
Group the three disks together using the smallest disk as the Parent.

This is a basic "Light w/halo" object. When rendering it be sure to always point the Y axis at the camera. It's easy to do: just Align Y axis to Track to Object Camera. Render that, and see what You get. In this example the smallest disk acts like the bright lightbulb, the second disk acts like the film burn area, and the third disk acts like the atmospheric dispersion area. The object, being 2D, has some limitations.

A primary limitation is that this object only works well in Scanline situations, this is because in Trace Mode the two larger Radial mapped spheres block the smaller disk's light travelling backwards. To work around it create an axis, make it a Lightsource, place it behind the larger disk, group it to the smallest disk. It isn't infallible, however...

Experiment with values. The Color values given above were for a standard high intesity lightsource. Alwa ys remember what Your lightsource would look like in the real world.

Fog method:

Create a primitive sphere.
Make it Bright with the Color values 255, 255, 255.
Copy the sphere and scale it slightly larger than the original sphere primitive.
Make this sphere a Fog object by experimenting with Fog Length values. Color it as necessary.
For those with Imagine v3.0 assign the Ghost texture to the foggy sphere, experiment with values.

If You're using Imagine 3.0 You can use the Sparkle texture. If You've downloaded Milan's textures (BTW, Thanx, Milan!) there is one itx in there that is useful, but my memory fails me as to the name. I don't have Essence, so I don't know what there might be in there. Hope this helps...

Here it is a more accurated step-by-step tutorial to create a glowing point light source based on this "Fog method":

Create a primitive sphere (Radius: 10.00).
Set the Fog Length value to 3.00.

Add the Ghost (Imagine v2.9 or higher) texture as follows:

 Column One     Two
     1500       0
        1       0
        0       0
        0       0
        0       0
        0       0
        0       0
        0       0

Add Fakely texture:

 Column One     Two
        0      80
        0      80
        0     200
        0     130
        0     130
        0     255
        0.95    0
        0       0

Make the object a Light Source.

Lens flare:

You could use the Lens Flare effect that comes with Imagine 3.0, just disable the flaring and have only the halo turned on. Easy.

Add a light in Imagine Stage Editor. "T" to transform the Axis. Make the size much larger than the default, make it 200 or even more. In the Action Editor, add the Lens Flare Global FX. Render!

This has always been in Imagine, but the default size is just too small! Remember, don't scale the light, transform it using "T" or Action Editor.

For added effect (actually, in lieu of the FX if You're pressed for render time... but the two TOGETHER work great...) create a ball or tube around Your light and make it Bright and Fogged. Track to camera. Render!

Follow this steps to create the light streak:

Add a primitive tube (Radius: 10, Height: 100, 4 sections).
Rotate y, 90 degrees.
Translate axis only z, 50 units.
Set axis Align to 0, 0, 90.
Set axis Size to 10, 10, 10.
Drag box, multi pick left most section points, scale them by a scale factor of 0; repeat for the right most section and for central one points.
Multi pick the two other sections points and scale it 75, x only.
Enter Attributes requester and set Light parameters (Red Intensity: 600, Green: 600. Blue 1500, Round Shape, Parallel Rays).
Modify the following attribs:

COLOR REFLECT FILTER SPECULAR

R 70 0 0 0

G 144 0 0 0

B 255 0 5 0

Dithering Hardness Roughness Shininess Fog lenght Phong

255 0 0 0 5.0 yes

	COLOR	FILTER
R	70	0
G	144	0
B	255	5

Dithering	Hardness	Roughness	Shininess	Fog lenght	Phong
255	0	0	0	5.0	yes

Add GHOST:

 Column One     Two
      200       0
        0.7     0
        0       0
        0       0
        0       0
        0       0
        0       0
        0       0

Remember the Global Lens Flare effect and modify the light streak y axis size to affect halo size; You could use this to simulate explosions, just modify the size and use some sort of explo anim brush filtered mapped plane.

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