Material Texture Layers

Materials can add more to a mesh than just a color. They can use images, text, or other patterns to give a material swirling color patterns (like marble), patchy reflections (like shiny metal scratches appearing beneath matte paint), or even complex glows of light (like the speckled pattern of glowing holes in a pierced metal light fixture).

These complex, realistic materials are easier to build and edit since they are combinations of simple layers. Use just one layer for a simple plastic surface, or many layers to create an upholstered shiny leather. By creating many layers, and changing the order of those layers, your material can start with a simple appearance and then build up the realism of your material when needed.

Understanding the Channels and Types in Material Textures

Build realistic materials by creating one or more texture types in separate channels to achieve different effects on a material. For each channel, one or more types can be applied: a composite of all the types for that channel is calculated and applied to the material. For example,

Managing Texture Layers

• Start with a simple grey material…
• Apply a color fill layer to the albedo channel to give it a color…
• Apply an image type texture layer to the albedo channel to give the mottled, random look of leather…
• Apply the same image type texture layer to the glossiness channel to give some areas a shine, while other areas remain dull…
• And finally a diamond stitching texture applied to a normal channel to give the material a raised, upholstered look without modifying the mesh beneath it.

A benefit to this layered approach is the level of control it gives you not just during design time, but also at run-time. Change the color fill layer to change the color of the leather. Apply a different image to the albedo or glossiness channels to change from alligator leather to ostrich. Apply a different texture to the normal channel, and the leather won’t look like a quilted, upholstered surface but a flat, embossed one with your corporate logo.

1. Select the material in the explorer on the left. The material’s properties appear on the right.

2. In the properties list, open the “Textures” expander to see the list of layers in this material.

• To add a new texture layer, scroll below the last texture. Click the New Layer button.

• To permanently delete a texture layer, click the context menu next to its name. Select “Delete texture layer.”

• To temporarily hide any texture layer, click the visibility icon next to its name. While hidden, the layer is not applied to the overall appearance of the material. Click the visibility icon again to restore it.

• To re-order texture layers within a channel, first scroll to that channel and see the multiple texture layers applied to it in a list. If that list has more than one item, you can drag any texture layer up or down in that list. A highlight bar will appear when it is dragged to a valid position. You cannot drag a texture layer from one channel to another.

Inheriting from a global material? Override your textures, don’t delete them.
If the material you’re editing is inherited from a global material, then you’ll notice that the base textures (inherited from that global material) cannot be deleted. Simply add another layer to the texture to override that global material.

Texture Layer Channels

A material’s appearance can be changed in many ways, which are grouped as “channels.” Each channel has one or more texture layers within it.

Texture Layer Types

Texture Layer Properties

Texture Layer Channel Name	Description
Albedo	A color texture define the colors reflected by the material’s surface.
Ambient	A grayscale map defines how much the material will be lit: the darker the grey, the less the material will be lit by any ambient lighting.
Ambient Occlusion	Color textures/Grayscale maps define what parts of the material will not be lit by ambient lighting.
Anisotropy Tangent	Only used is Anisotropy is enabled. The red, green, and blue colors in this texture define the tangent of the anisotropy (red is U, green is V, and blue is intensity).
Clear Coat Normal	Only used if Clear Cloat is enabled. The colors in this texture define the bump map of the clear coat.
Emissive	A grayscale map defines what parts of the material will be producing its own light. The darker the grey, the less glow that part of the material will have.
Metallic	Grayscale maps show areas of the material which reflect light like polished metal. The darker the grey, the duller the finish on that part of the material.
Normal	Color textures or “bump maps” which give the appearance of depth to the surface, without modifying the actual geometry of the mesh. For example, give the appearance of screw threads on a simple cylinder, or the apperance of diamond plate to a flat sheet of metal. The 3 colors in this texture define the height and direction of the “bump” in the bump map.
Opacity	Grayscale maps defining opacity of a material, where white is completely opaque and black completely transparent.
Reflection	Color textures rendered on glossy or reflective parts of the material, instead of the environment
Roughness	Grayscale maps defining the roughness of the surface.
Subsurface Thickness	Only used if Refraction or Translucency is enabled. The greyscale pixels in this material define the apparent thickness of the material, where black is zero (no thickness) and white is the full thickness defined in the property.

Layer types are different ways to manipulate a channel. Add a texture layer of one type to a channel, or add many texture layers of various types to a channel. Texture layers can be combined for sophisticated visual effects.

When you add a texture layer to a channel, it will be one of these fundamental types:

Texture Layer Type Name	Description
Image texture	The most common layer type: an image (either grayscale or color) describes a complex pattern. Natural patterns (woodgrain, blades of grass, etc) are often expressed as image textures.
SVG Texture	Use the precision of math to define a precise pattern using Scaleable Vector Graphics (SVG). You can also make words or text appear in this texture.
Color Fill	Apply a simple color fill to your channel. Unlike the other types, color fill has no texture: there’s no variation to it. Color fills are often used as a starting point for a channel, or a finishing touch.

Regardless of the type of texture you apply to a channel, that texture layer will have these properties:

Property	Snap Property	Description
U-Scale / V-Scale	uScale / vScale	1:x scale of the fit box relative to the full generated texture
U-Offset / V-Offset	uScale / vScale	Offset of the texture relative to the full generated texture
Angle	wAngle	Rotation angle of the texture fit box
Pivot U / Pivot V	uPivot / vPivot	Pivot point for scaling and rotation of the texture fitbox relative to the full texture (0.5, 0.5 centers the pivot point)
U-Alignment / V-Alignment	verticalAlign / horizontalAlign	Alignment of texture within the fit box. No effect on the first texture in the layer.
U-Fit / V-Fit	verticalFit / horizontalFit	Fit of texture within the fit box. No effect on the first texture in the layer. Stretch - always fit the texture to the full width/height of the generated texture Contain - If the texture is larger the generated texture, shrink it so it fits
Maintain Aspect Ratio	maintainAspect	Maintain aspect ratio of source image during any resizing
Tile	tile	Repeat textures that are overlaid. Has no effect on the first texture in the layer.
Colorize	colorize	Color texture with a chosen color. Does not affect luminosity.
Blending Mode	blendMode	See underdeveloped-US/docs/Web/API/CanvasRenderingContext2D/globalCompositeOperation
Texture Strength	strength	How strongly the given texture layer affects the entire texture
Flip Channels	flip	When using a color bitmap to simulate depth (such as on a bump map), this changes the dimensions (U or V) mapped to the red and green colors in that bitmap. For example, if your concave bumpmap surface appears convex (or vice versa), check this box to fix.

Designing Materials with Texture Layers

Material design is its own art form, with many professionals making a career out of the task. Fortunately, you can purchase and import materials with their texture layers intact. Then adjust those layers to fine-tune the material to your needs. If you are designing your own materials from scratch, try extending the built-in library materials, to see how they are built.

1. Click the materials tab along the bottom of the screen to find a library material that could be similar to the one you want to design.

2. Apply the library material to a mesh in your scene. You can drag it onto the mesh, for example.

3. Open the mesh’s properties: you’ll see the material listed, with an extend button next to it.

4. Extend the material: you now see the extension of the material listed in the scene’s explorer tree, named “Copy of… [material]”.

5. Click that node in the explorer tree of the new, extended material.

• Investigate the material properties.
  The properties appear on the right. Many properties have a pencil next to them: click the pencil to see details of that property.

• Investigate the material textures.
  The Textures for the material also appear on the right, in their own related list. Open the list to see how your texture is built. For example, maybe it starts with an Albedo texture, then an ambient occlusion texture, followed by a normal texture and a roughness texture.