Texture

Definition: A texture is an image that is applied to the surface of a 3D model, where it describes properties such as color, gloss, roughness or fine unevenness. The geometry defines the shape, and the texture defines the appearance of the surface. Only with textures does a brushed stainless steel sheet look like metal and not like gray plastic.

In B2B mechanical engineering, textures are used for: photorealistic product visualization in sales, 3D viewers on websites and trade show kiosks, AR presentations at the customer site, VR design reviews, and training applications in which operators must recognize components by their appearance.

Advantage: A textured model shows the material and the build quality of a machine, without making the geometry heavier.

English: Texture, Texture Map
German: Textur, Oberflächentextur

How It Works

UV mapping: from the image to the surface

So that a 2D image lies correctly on a 3D body, the model needs a UV layout:

1. Unwrapping: The surface is unfolded into a plane like a sewing pattern (axes U and V).
2. Placing seams: The cut edges are put in hidden locations, for example on housing edges.
3. Assignment: Each vertex of the model gets a coordinate in the image.
4. Rendering: While drawing, the GPU reads the matching texture value for each pixel.

Difference from CAD: CAD data describes surfaces mathematically and usually contains no UV coordinates. On the way into the 3D pipeline, the surfaces are triangulated and unwrapped again.

PBR: physically based materials

Physically based rendering (PBR) describes surfaces with parameters that are based on the behavior of real light. In the metallic-roughness model of glTF 2.0, these maps are typically used:

In glTF, metallic (blue channel) and roughness (green channel) are in one shared image, and ambient occlusion can be in the red channel of the same image. This saves files and memory.

Typical surfaces in mechanical engineering

• Metal: A high metallic value. Roughness controls the difference between blasted, brushed and polished.
• Paint: A non-metal with the base color in the paint color. For high-gloss or multi-layer paint, there is the extension KHR_materials_clearcoat (clear coat layer).
• Rubber and plastic: High roughness, often a normal map for structure, for example on conveyor belts, seals or handles.

Bitmap and procedural textures

Most textures in real-time applications are bitmaps, that is, pixel images. Procedural textures, on the other hand, are calculated with a formula and are sharp at every size. Rendering programs often use them for noise, ground finishes or grain. For web and mobile, procedural materials are usually converted into bitmaps in advance (baked), because viewers and AR formats cannot evaluate them directly.

B2B Applications

Sales and product visualization

Customers also judge machines by their look and feel. Clean PBR textures show food-grade stainless steel, powder coating or privacy screens realistically. A model with PBR materials looks consistent in the browser, on the tablet and in the AR headset, because all platforms evaluate the same parameters.

Trade show and kiosk

On large touchscreens, weak textures are immediately visible. Here, higher resolutions are worth it, because kiosk hardware is usually more powerful than a smartphone. With real-time rendering, you can switch paint colors and equipment variants live, for example in 3D product configurators.

Service and training

Technicians often recognize components by color and labeling: yellow warning markings, type plates, color-coded lines. Textures make these features visible in maintenance instructions and VR training.

Design review

A design review is usually about shape and installation space, not about photorealism. Simplified materials are often sufficient. But for reviews about look and feel, for example color concepts for a new product series, realistic paint and metal textures are mandatory.

Texture Optimization for Web, Mobile and XR

Textures are often a large part of the file size and the GPU memory of a 3D model. So if you use the same model on several platforms, plan the textures from the start.

Proven measures:

• Resolution that suits the platform: Desktop and kiosk can handle larger textures than smartphones and standalone headsets.
• GPU texture compression: JPEG and PNG are fully decompressed on the graphics card. KTX 2.0 with Basis Universal, on the other hand, stays compressed in the GPU memory too and is converted at runtime into the format of the device. In glTF, this is done with the extension KHR_texture_basisu.
• Texture atlas: Combine several small textures in one image. This reduces draw calls.
• Tileable textures: For large, uniform surfaces (floor plates, perforated sheets), a small pattern repeats.
• Mipmaps: Reduced levels of the same texture prevent flicker on distant objects.
• Bake details into the normal map: Small holes, screws and embossing as relief instead of geometry.

For AR on iOS, the model is usually delivered as USDZ, which also supports PBR materials. This way, you can use one well-built PBR material from one source for the web, WebGL viewers and AR apps.

Frequently Asked Questions (FAQ)

What is the difference between a texture and a material?

The material is the complete description of a surface: which lighting model applies, and which values are used for color, metallic and roughness. Textures are images that supply these values for each pixel. A material can also work without a texture and use fixed values, for example for sheets painted in one color.

Can you take over textures directly from the CAD system?

Usually not. CAD systems often store materials as color values or in their own libraries, without a UV layout and without PBR maps. For real-time applications, textures are created in a separate work step or assigned from material libraries.

Why does a model look different in the browser than in the rendering program?

Real-time viewers calculate simplified lighting to stay smooth. Differences come mainly from ambient light (environment map), color space settings and missing PBR channels. Solution: work consistently with PBR and check the model on the target platforms.

How many textures does a machine model need?

This depends on the use. For a web viewer, a few shared materials with combined maps are often sufficient. For close-up views on the trade show kiosk, a much more detailed set can make sense. The important thing is to avoid unnecessary duplicates.

Do logos and type plates belong in the texture?

Yes, labels are usually applied as a texture, not modeled. Make sure that the resolution in this location is sufficient, so that the text stays readable also when you zoom in.

Industry Standards and Technologies

• glTF 2.0 (Khronos Group) – Exchange format for real-time 3D with metallic-roughness PBR
• KTX 2.0 and Basis Universal – GPU texture compression for all platforms
• KHR_materials_clearcoat – glTF extension for clear coat layers
• OpenUSD – Scene description, the basis of USDZ
• MaterialX – Open standard for the exchange of material definitions
• Learn OpenGL: PBR Theory – Introduction to physically based rendering

Related Topics

3D basics: - 3D model – Geometry and structure - 3D pipeline – From CAD to the real-time model - Real-time rendering – Display in real time - UV mapping – Unwrapping of surfaces - Shader – Programs for the display of surfaces

Formats and standards: - OBJ – Simple 3D format with a material file - USDZ – AR format for Apple devices - glTF – Web 3D format with PBR - KTX 2.0 – Compressed textures

Platforms: - WebGL – 3D in the browser - Augmented reality – AR basics - Virtual reality – VR technology - visionOS – Apple's platform for spatial applications

Applications: - 3D product configurators – Variants in real time - Digital twin – Digital copy of a system - Immersive experience – Realistic display - Product visualization – Materials in sales - Level of detail (LOD) – Detail levels for performance