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Material Structure
A material is made up of fourteen channels. Each of these channels defines a different property of an object's surface. When you combine all the channels together you get a material.
New materials are created by adjusting the values for each channel.
There are two types of materials you can create in Bryce: surface materials, which define the properties of an object's surface, and volume materials, which define the properties of an object's volume.
Understanding Surface Material Channels
The fourteen channels of a surface material each represent a different surface property. These properties simulate different physical properties of a surface, and the combination defines how the object's surface interacts with light in the Bryce environment.
To understand how the channels work, you need to understand a little about how you perceive light and color.
The color and size of an object are determined by how the light that hits the object is reflected back to your eye. Objects appear green because they reflect green light. An object appears shiny because it reflects light back at you.
An object appears transparent because light passes through its surface, hits the objects behind it and is reflected back through the surface. Bryce's material channels simulate all these behaviors. When you set a channel value, you're setting how your object's surface interacts with the light that hits it, whether that light is from a direct source like the sun, or an indirect source like light reflected off other surfaces.
When you're creating volume materials, your settings not only control how light interacts with the surface of the object, but also how it interacts with the object's volume.
The effects of the channels are additive, meaning that each value you set directly affects all the other values. So, if you set the Diffuse Color to yellow and the Ambient Color to blue, the object will have a greenish tint.
Channels are interdependent. For example, you won't see the effects of the Transparent Color if the object is not transparent.
When you're using these channels it's important to understand the physical property they're simulating. Only in this way can you make meaningful adjustments to the component values.
For example, if you set both Transparency and Reflection to 100, you'll get an unusually bright object that doesn't look very realistic. The reason for this is that the object is emitting more light than it is receiving, something it couldn't do in reality.
Since material channels simulate real-world surface properties, you should try to keep channel values within a realistic range.
A good rule of thumb to keep in mind while you're setting these channels is that the Transparency and Reflection channels should always add up to 100, and the Diffusion and Ambience values should also always add up to 100.
Each surface material is made up of fourteen channels, divided into three groups:
Color channels
Value channels
Optics channels
Color Channels
The Color group contains all the channels that control the color reflected off an object's surface. The channels in the Color group are Diffuse Color, Ambient Color, Specular Color, Transparent Color and Volume Color.
Diffuse Color, Ambient Color, and Specular Color define the colors the surface reflects when direct light hits it. For example, Diffuse Color defines the color that is reflected in all directions when direct light hits the object, and Specular Color is the color that appears in the object's highlight.
These color channels are directly related to the Diffusion, Ambience, and Specularity channels. Diffusion, Ambience, and Specularity control how light reflects off the object, while Diffuse Color, Ambient Color and Specular Color control the color of that light.
So, for example, if you selected yellow as the Diffuse Color, the object appears yellow. The intensity of the yellow color is controlled by the Diffusion channel. Refer to "Diffuse Color", "Ambient Color", and "Specular Color" for more information.
Transparent Color sets the color of any light that passes through the surface of the object, and Specular Halo controls the size of the highlight that appears when an object has a shiny surface. Refer to "Transparent Color" and "Specular Halo".
The remaining color channel, Volume Color, controls the color of the interior of the object. Refer to "Volume Color" for more information.
Value Channels
The second group of channels, the Value group, controls how much light affects an object. The channels in the Value group are Diffusion, Ambience, Specularity, Metallicity and Bump Height.
Diffusion, Ambience, and Specularity define how the surface interacts with direct light. They let you control how much direct light affects the surface of an object. In a physical environment, these channels control how shiny, dark, or bright the object appears. Refer to "Diffusion", "Ambience" and "Specularity" for more information.
Metallicity is related to Reflection. It determines how much reflected light is filtered through the Diffuse Color. Refer to "Volume Material Channels" for more information.
Bump Height controls the height of any bumps or dents on the object's surface. Refer to "Bump Height" for more information.
Optics Channels
The Optics group of channels controls the intensity of optical effects produced by the object's surface. The channels in the Optics group are Transparency, Reflection and Refraction.
Transparency and Reflection channels control how indirect light interacts with the object's surface. In a physical environment, these channels control how transparent or reflective the object appears. Refer to "Transparency" and "Reflection" for more information.
Refraction is directly related to Transparency. The Refraction channel sets how much the light that passes though the object is bent. Refer to "Refraction" for more information.
Understanding Volume Material Channels
Surface materials define the properties of the surface of an object. The interior of the object is empty. If you were to fly through the object you would see one layer of material, emptiness, and then another layer of material. A volume material is applied to the entire object, both inside and out. If you were to fly through a volume material you would be surrounded by material.
When you create a volume material, the channels define not just the surface of an object, but its volume as well.
When you're setting channel values for a volume material, you're setting up how light will interact with the object's volume. Channels control whether the interior of an object is bright, dark, shiny, or transparent.
In most cases the interior of an object will be filled with a texture. If so, the channels control the surface properties of the elements within the texture.
For example, if you apply blue spots as a volume material, you get a volume filled with blue spheres. The channels then control whether those spheres are bright, dark, shiny, or dull.
Volume materials are made up of thirteen channels, divided into three groups:
Color channels
Value channels
Volume channels
The channels in the Color and Value groups work exactly as they do for surface materials, except that the channel settings are applied to the object's volume instead of its surface.
Volume Channels
The Volume channels control special volume properties of the object's interior.
Base Density controls the density of the object. This channel defines how much material there is in the interior of an object. As a result, Base Density controls how much light passes into the object. A solid object doesn't allow any light to pass through it, while less dense objects allow more light in. Refer to "Base Density" for more.
Edge Softness, Fuzzy Factor, and Quality/Speed control the appearance of texture elements within the material. Edge Softness and Fuzzy Factor control the quality of the edges and sharpness of the texture, while Quality controls the render quality of the material. Refer to "Edge Softness", "Fuzzy Factor", and "Quality/Speed" for more.
Understanding Material Components
Each Bryce material channel can contain up to three components that determine the channel's setting. A component can be a color, a texture or a numerical value. A texture can be either a 2D texture (picture) or a 3D texture.
Each Bryce material channel contains components that determine its settings.
You can have up to three texture components in a channel, and some channels let you use four textures and a value as components.
Colors can only be used in the Diffuse, Ambient, Specular Transparent, Specular Halo and Volume channels. Values are used in the Diffusion, Ambience, Specularity, Metallicity, Bump Height, Transparency, Reflection, Refraction, Base Density, Edge Softness, Fuzzy Factor, and Quality/Speed channels.
When you're using a texture as a component, the information in the texture's channels is used as the value of the material channel. For example, if you're using a texture to set Diffuse Color, the texture's color channel is used. If you're using a texture to set the Diffusion value, the texture's alpha channel determines the Diffusion intensity.
Components are combined using one of three modes: Mode A, Mode AB and Mode ABC. In Mode A, only one component is used to set the channel's value. In Mode AB, two components are combined to set the channel's value, based on altitudes. The values from texture A are applied at low altitude and values from texture B are applied at higher altitude.
In Mode ABC, the values of two textures, A and B, are blended based on the alpha channel of texture C.
When you're using textures as a component, you can choose from a number of preset textures, or you can open the Texture Editor and create your own textures. Refer to "Combining Components" for more information.
In some channels, you can use both a texture and a value. In this case, the value determines how much of the texture's value is used to drive the channel. For example if you apply a Blue Checkers texture to the Bump Height channel, the texture sets the shape of the bumps and the value sets how prominent those bump appear.
A Word About Alpha Channels
One of the outputs a texture component can produce is an alpha channel. The alpha channel is a grayscale representation of the texture pattern or grain. When you use a texture as a component in a material channel, these grayscale values are used to map surface properties. White areas in the alpha channel represent 100% of the effect, and black areas represent 0%.
Images, or 2D textures, also contain an alpha channel. In images, the alpha channel acts as a mask for the image. The image's alpha channel is used in the same way as a texture's alpha channel.
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