Walker Effects Manual
- Installation
- Alpha Tool
- Channel Composite
- Channel Lighting
- Channel Noise
- Channel Offset
- Channel Range
- Channel Viewer
- Color Composite
- Color Fill
- Colorize
- Color Space
- Composite
- Crazy Stripes
- Glow
- Gradient Designer
- Light Wrap
- Stargate
- Super Histogram
Channel Lighting
Channel Lighting is an alternative approach to 3D lighting and offers compositors the ability to control 3D lighting within After Effects. This can save an enormous amount of time by simplifying long 3D renders and having the ability to endlessly tweak and create variations on lighting. Furthermore, since all the 3D is pre-rendered, Channel Lighting is very fast and gives immediate feedback to changes. This can save hours of wasted time waiting for 3D renders.
The process works similarly to other multi-pass rendering techniques, but with some unique differences. First, the diffuse and lighting passes are separated so that the light can be controlled without affecting the natural colors of objects. Second, the lighting passes are rendered into a single file by separating lights into groups and rendering them into the red, green and blue channels... thus the name Channel Lighting. Setting up these renderings is discussed in further detail below.
Most 3D rendering programs are capable of generating the render passes needed by Channel Lighting, though it may require a bit of technical creativity. The following instructions should help you setup the render passes properly no matter what program you are using:
In order for Channel Lighting to be most effective, you also want to separate lighting into groups that can be treated as individual lights in After Effects. For example, if you were creating an outdoor scene, you may have one key sun light, reflected light from the ground, and general light from the sky. No matter how many lights you are actually using, they can be grouped together to produce generalized lighting passes.
While you could render each lighting pass separately, it is better to use the Channel Lighting approach and store multiple lighting passes in a single file. This is accomplished by setting the light colors to full red, green, or blue. By setting the light colors this way you limit rendering of the light to just one channel (red, green, or blue). This makes it possible to have 3 distinctly separate render passes in one file. Most lighting situations can be represented by 3 render passes, however Channel Lighting supports up to 6 different passes. Be sure that when specifying light colors that you use absolute red, green, and blue values, otherwise the lighting passes will mix. In After Effects, Channel Lighting is used to apply the lighting over the diffuse pass.
When you are setting up your scene lights, you really don't need to spend a lot of time. The following tips will help you create good lighting passes quickly:
Though this approach to 3D lighting is at first foreign, it is actually very simple and produces great results. For just a little bit of extra setup time you get much greater control and will spend less time in 3D rendering.
Note: The Light Group name can be changed by clicking on 'Options' in the Effect Controls Window.
The process works similarly to other multi-pass rendering techniques, but with some unique differences. First, the diffuse and lighting passes are separated so that the light can be controlled without affecting the natural colors of objects. Second, the lighting passes are rendered into a single file by separating lights into groups and rendering them into the red, green and blue channels... thus the name Channel Lighting. Setting up these renderings is discussed in further detail below.
Most 3D rendering programs are capable of generating the render passes needed by Channel Lighting, though it may require a bit of technical creativity. The following instructions should help you setup the render passes properly no matter what program you are using:
Creating the Diffuse Pass
The first render pass required by Channel Lighting is a fully ambient color pass. Typically, you can set this up in 3D by turning off all your scene lights, and setting ambient light to 100%. In some programs, the ambient may be built into global controls and in others you may need to create a new light object. The end result should be full illumination everywhere with no shadows or unlit areas. The render should look flat with no dimension, and every object should be in full color.Creating the Lighting Pass
The second render pass needed by Channel Lighting is the lighting pass. The lighting must be isolated from the scene colors by giving all of the objects in the scene a matte white color with no textures. In some programs you can apply a global texture or project a camera map over the scene to get this effect. In other applications, you may need to duplicate all of the objects and have one set that is white (for the lighting pass) and the other set that is textured and colored properly (for the diffuse pass). For the best lighting results, be sure to leave on bump and displacement texture maps as they affect how the light interacts with surfaces.In order for Channel Lighting to be most effective, you also want to separate lighting into groups that can be treated as individual lights in After Effects. For example, if you were creating an outdoor scene, you may have one key sun light, reflected light from the ground, and general light from the sky. No matter how many lights you are actually using, they can be grouped together to produce generalized lighting passes.
While you could render each lighting pass separately, it is better to use the Channel Lighting approach and store multiple lighting passes in a single file. This is accomplished by setting the light colors to full red, green, or blue. By setting the light colors this way you limit rendering of the light to just one channel (red, green, or blue). This makes it possible to have 3 distinctly separate render passes in one file. Most lighting situations can be represented by 3 render passes, however Channel Lighting supports up to 6 different passes. Be sure that when specifying light colors that you use absolute red, green, and blue values, otherwise the lighting passes will mix. In After Effects, Channel Lighting is used to apply the lighting over the diffuse pass.
When you are setting up your scene lights, you really don't need to spend a lot of time. The following tips will help you create good lighting passes quickly:
Light Range
Make sure there are no blown-out hotspots by setting light intensities appropriately. Also be sure there are no large voids, or completely black areas. Both can create problems in lighting later.Shadow Quality
Create your lights to produce shadows with the right amount of softness you are looking for. The shadow softness can be tweaked in Channel Lighting using Gamma and Intensity, but it will affect surface shading as well.Light Direction
The one variable that cannot be changed in Channel Lighting is the direction, so make sure that your lights are placed fairly accurately in 3D. Otherwise, you may need to re-render the lighting pass later.Though this approach to 3D lighting is at first foreign, it is actually very simple and produces great results. For just a little bit of extra setup time you get much greater control and will spend less time in 3D rendering.
View Mode
The View Mode controls the output and display options of Channel Lighting so that you can work on individual parts of the plug-in more easily. With the View Mode, you can work on a single light layer, view the source layers, or see all the lights pre-computed. Note: Only controls relevant to the selected View Mode will be enabled. To enable all controls, set the View Mode to Final Composite.Diffuse Layer
The Diffuse Layer is the layer that light is applied to. Choosing this View Mode will display the selected Diffuse Layer without alteration. If None is selected, then the layer on which the plug-in is applied will be displayed.Master Light Layer
Choosing this View Mode will display the Master Light Layer. This layer defines the source channels for the light. The Master Light Layer is used by every light that does not explicitly specify a different layer.Light 1 Layer (1-6)
Each Light Layer View Mode displays the source layer for that light. When the light does not specify its own source, then the Master Light Layer is used.Light 1 (1-6)
Each Light View Mode displays the processed light source. The specified channel is extracted from the Light Layer and then adjusted based on the Light Color, Ambient, Gamma, Intensity, and any other settings. Use these View Modes to see what each light is doing individually. Note: These View Modes do not composite the light over the diffuse channel nor account for the master controls, but rather show the light channel by itself. Also the pre-computed light passes are unmatted and have no transparency, so expect to see a bit of fringing at the edges.Light Composite
The Light Composite View Mode will show all of the light sources processed and combined together before applying it to the Diffuse Layer. This is where you can best see how lights are interacting with each other and fine tune the settings before the final composite.Final Composite
This View Mode renders the complete Channel Lighting process and composites the light over the Diffuse Layer.Diffuse Layer
The Diffuse Layer is the full ambient color render pass of your 3D scene. Although it is possible to choose any layer, it is more efficient to leave the Diffuse Layer popup menu to None and apply Channel Lighting directly to the diffuse render pass. For more information on the Diffuse Layer, see 'Creating the Diffuse Pass' in the introduction.Master Light Layer
The Master Light Layer specifies the lighting pass layer. Typically the lighting pass layer in the Timeline Window is turned off and used only by this effect. All lights in Channel Lighting will automatically use the Master Light Layer unless explicitly specified otherwise. For more information on the lighting pass, see 'Creating the Lighting Pass' in the introduction.Master Ambient
This specifies the overall Ambient amount for all lights. Ambient sets the minimum brightness for light and brightens the dark areas. If Ambient is set to 100%, then the scene will be fully illuminated.Master Gamma
Each light's Gamma value is factored with the Master Gamma. The Gamma value is used to adjust the range of light, biasing it towards darker or lighter. Increasing the Gamma will broaden the coverage of light, while decreasing Gamma will decrease the lights range and make the shading drop-off sharper. The default value of 1.0 has no affect.Master Intensity
The Master Intensity is multiplied with each light's Intensity and affects overall brightness of light. The Intensity value multiplies the light value either diminishing its effect or increasing it. And as with lighting in 3D, it is possible to have high Intensity values to make lights very bright. Negative values are not allowed for Intensity, however you can create subtractive lights by changing the Composite Mode to Subtract.Final Composite Mode
How lighting is applied to the Diffuse Layer is controlled by the Final Composite Mode. The default mode is Multiply which is the operation used by 3D programs to apply lighting to objects. However, it is possible to use other composite modes to produce other types of effects. For example, Channel Lighting can be used to apply reflection and specular passes, in which case the Final Composite Mode would be Add, instead of Multiply. But for general purposes, it is best to use Multiply. Note: This control is not related to the Composite Mode of each Light Group.Light Group
Channel Lighting supports up to 6 lighting groups, each with its own set of controls for specifying a complete lighting pass. A Light Group is enabled by turning on the Enable checkbox. Unused Light Groups are displayed in gray text. Each enabled Light Group will require additional rendering time by Channel Lighting.Note: The Light Group name can be changed by clicking on 'Options' in the Effect Controls Window.
Enable
This checkbox determines whether the Light Group is being used or not. When Enable is off, the group controls will be disabled and appear gray. You can use this checkbox to quickly toggle lights on or off. It is very helpful for isolating individual lights while setting up the controls.Use Master Light Layer
By default Use Master Light Layer is turned on, which means that the Light Group will get its lighting channel from the Master Light Layer. If you have another layer that you wish to use as a lighting pass, simply turn off this checkbox and the Light Layer control will become active.Light Layer
You can use this control to specify an alternate lighting source for the Light Group. To use this feature, you must turn off the Use Master Light Layer checkbox.Channel
Channel Lighting is designed to use single grayscale channels as lighting passes. If you use the RGB method of lighting (ie lighting passes separated in the red, green and blue channels) then you can pick a lighting pass by setting this Channel. By default, the Light 1 group uses the Red channel, Light 2 uses Green, and Light 3 uses Blue.Invert
Turn this checkbox on in order to invert the Channel values. Under normal circumstances, Invert would not be needed, however if you are building specialized lighting passes it can be helpful.Premultiply With Alpha
This option will premultiply the Channel value with the Light Layer's alpha channel. Normally this is not desirable as it tends to create dark edges around objects. However, if you are using special light passes, it may be necessary to premultiply the Channel.Light Color
This sets the color of the light, just as you would set the light color in 3D. Light Color is pre-computed into the Light Group and is subjected to Intensity and Gamma values, so it is possible to have resulting color that is brighter or darker than the color you pick.Shadow Color
This color specifies the darkest color of the light and is useful for tinting areas in shadow.Shadow Level
This slider controls the black point of the light. Increasing Shadow Level will create a darker shadow region.Ambient
Ambient increases the amount of light by adding to it. You can use Ambient to bring a touch of light into really dark areas. The Ambient value for each Light Group is also affected by the Master Ambient control. Keep in mind that using Ambient light tends to flatten the whole composition, and it generally looks better not to use it.Gamma
Gamma is used to bias the Channel midrange values towards black or white. The lower Gamma is, the less area the light will cover. With larger values of Gamma, the light coverage is increased and tends to create more contrast. Gamma is factored with the Master Gamma control.Intensity
The Intensity value multiplies the light value and will increase or decrease the power of the light. It is possible to set Intensity to values greater than 1 to produce very bright lights. Negative values are not allowed, however you can create subtractive lights by setting the light's Composite Mode to Subtract. The Intensity is factored with the Master Intensity value as well.Composite Mode
All of the lights in Channel Lighting are pre-computed before applying to the Diffuse Layer. The Composite Mode of each light determines how it interacts with the other lights. Typically, Add is the desired method of combining lights. However, you can use other modes such as Subtract to create other types of light interaction. Keep in mind that the Composite Mode does not affect how light is applied to the Diffuse Layer.Options
Channel Lighting has a special dialog window that allows you to rename the light groups. This can be helpful to organize your project better. To invoke the Options Dialog, click on 'Options...' in the Effect Controls Window.
