Waviness (Aesthetix)
Waviness is a surface appearance parameter that quantifies the strength of orange peel – surface waves that distort reflections on otherwise glossy surfaces.
Parameter description
Waviness describes larger‑scale texture features on the surface (typically in the 0.1–10 mm range) that cause reflected straight lines to appear wavy rather than perfectly straight. Higher waviness values indicate more pronounced orange peel and a more obviously distorted reflection, while lower values correspond to smooth, piano‑like finishes with minimal visible structure.
How is it measured?
- The instrument projects a line or pattern onto the surface and records the reflected image using the observer camera.
The distortion of the reflected of a straight line is captured by the observer camera. The visual effect of orange peel can seen in the reflected test charts on the right of the camera images.
- Software analyses how much the reflected line deviates from a mathematically straight reference; these deviations are converted into a waviness value (WU) that is calibrated to align with perception‑based orange‑peel scales at a typical viewing distance of around 1.5 m.
Interpretation of values
- Very low WU values correspond to “piano finish” surfaces with virtually no visible orange peel and a strong impression of quality.
- Increasing WU values move through low, standard and high orange‑peel ranges, where the texture becomes clearly visible and increasingly negative for perceived surface quality, especially on dark, high‑gloss colours.
Applications
- Setting and monitoring orange‑peel targets on automotive body panels, bumpers, commercial vehicles and yacht coatings to match appearance standards.
- To improve wavines- optimise coating systems, spray parameters, viscosity and curing conditions, waviness may also "telegraph" through from an imperfect substrate.
Here is a parameter table for Waviness:
| Item | Specification / Value |
|---|---|
| Index name | Waviness |
| Unit | WU (Waviness Units) |
| Description | Quantifies orange peel –surface undulations that distort reflections |
| Measurement geometry | Specular reflection using projected line light and observer camera at fixed distance and angle |
| Analysed distance | 20mm line on surface. mm |
| Other analysed areas | Effect / Texture / Polishing modules: up to 10 Ă— 10 mm or 15 Ă— 15 mm, depending on configuration |
| Perceptual basis | Scale aligned to human perception of orange peel at ~1.5 m viewing distance (correlated to Rhopoint TAMS scale) |
| Typical value ranges (automotive) | < 2 WU: piano finish; 2–5 WU: low orange peel; 5–10 WU: standard orange peel; 10–15 WU: high orange peel |
| Measurement range | Approx. 0–30 WU |
| Repeatability (typical) | ±0.5 WU |
| Reproducibility (typical) | ±1.0 WU |
| Primary use | Setting and monitoring orange‑peel levels on high‑gloss coatings such as automotive, marine and furniture |