Part 1 What is a "Texture Map" Essential for Representing Optical Properties?

June 29, 2026

When we talk about optical properties in 3D design, we’re really asking: how does a material interact with light? Does it reflect light like polished metal, absorb it like velvet, or bend it like glass? In the world of 3D graphics, these qualities are expressed using something called a texture map—essentially an image file that gets wrapped around a 3D model to give it realistic surface details. There isn’t just one type of texture map. In fact, there are several, and each serves a unique purpose in creating depth and realism. For instance, one texture map might define the base color, while another adds the sense of roughness or gloss. When layered together, they can transform a plain 3D object into something that looks and feels lifelike.

Take a look at the example: on the left, you see an object without any texture maps applied—it looks flat and uniform. On the right, once the texture maps are in place, you can see not only the color but also the subtle bumps and surface variations that give the object a tangible presence. This is the power of texture mapping in bringing digital fashion assets to life.

texture map

There are many types of texture maps, and by combining them, you can create surfaces that look remarkably realistic.

Let’s take a closer look at different types of texture maps and how each contributes to the overall material expression.

A Closer Look at Different Types of Texture Maps

Base Color Map

Also known as a Diffuse or Albedo map, this type defines the basic color information of a material. The example here shows the base color map of a woven fabric-like texture that captures the fabric’s appearance.

sample_BASE

When this base color map is applied to a 3D object, as shown below, you can see that only the color is expressed. Because no surface depth information is included, the material looks flat and lacks realism — there’s no sense of texture or dimensionality yet.

Normal Map

A Normal Map is used to simulate the small surface bumps and textures of a material.
It’s built from RGB (Red, Green, Blue) values, where each color channel represents a direction (X, Y, and Z) of the surface. By varying the intensity of these colors, the map gives the illusion of depth and three-dimensional detail.

sample_NRM

When a normal map is applied together with a base color map to a 3D object, as shown below, you can see how it adds realistic fabric texture and shading.
However, the effect is limited to the surface—it doesn’t actually change the geometry. The object’s edges remain flat. To create genuine surface displacement, including raised or indented edges, a different type of map called a Displacement Map is used.

Normal_applied 　 Normal_applied_exp

Displacement Map

A Displacement Map is used to add real three-dimensional relief to a flat 3D surface. It uses a grayscale gradient, where white represents raised areas and black represents recessed ones. Compared to a normal map, it provides a much more realistic sense of three-dimensionality. As you can see from the example, applying a displacement map gives the object visible height variations—even along the edges.

sample_DISP 　 Displacement_applied

One thing to note: because this process actually modifies the mesh geometry, it can be computationally heavy and take longer to render, so it’s best to apply this map only when you really need that extra level of realism. Also, some render engines may not fully support displacement maps or may require additional settings to enable them.

Alpha Map

Also known as an Opacity Map, this texture defines which parts of a surface are transparent and which are visible. It’s typically a black-and-white image: the white areas remain visible, while the black areas become fully transparent. For sheer or lace-like fabrics, applying an Alpha Map helps you achieve that delicate see-through quality in 3D.

Roughness Map

A Roughness Map defines how rough or smooth a material’s surface appears.
In this map, white areas represent rough, matte surfaces, while black areas indicate smooth, glossy ones. For example, in a woven fabric that uses metallic (lamé) yarns like the one shown below, the areas without metallic threads appear white—indicating a rough texture—while the sections with metallic yarns appear black, representing shiny, reflective surfaces.

V01_LAME NAVY_ROUGH 　 Roughness_applied

Metalness Map

A Metalness Map—sometimes also referred to as Reflectance or Gloss—defines how reflective a surface should appear. In the context of apparel materials, metalness maps are often used to represent metallic finishes—such as foil prints, coated fabrics, or sparkly effects created with metallic (lamé) yarns.

The above content is reproduced from “wearware ”

wearware | Supporting the Digitalization of Fashion Design (shimaseiki.com)