Normal map

Ensure that the given image meets the criteria for a normal map.

Parameter table

No parameter available.

Detailed description

This rule evaluates whether the given image qualifies as a normal map. A normal map is a type of texture map commonly used in 3D rendering to simulate surface detail.

To determine if an image is a normal map, we consider its visual characteristics. A normal map typically encodes surface normals, which define the direction that each point on a surface is facing.

In a normal map, different colors represent different surface orientations. Blue is often used to represent the z-axis (up and down), while red and green represent the x and y axes, respectively.

We assess the image by analyzing the distribution of colors and the relationships between them. Specifically, we look for the following criteria:

• The squared norm of the RGB vector of each pixel falls within a predefined acceptable range. This ensures that the colors in the image represent valid surface orientations and do not deviate significantly from expected values.
• The mean value of the blue channel is greater than or equal to the mean values of the red and green channels. This condition helps to ensure that the image accurately represents surface normals and maintains consistency in orientation across the surface.

By examining these characteristics, we can determine whether the image qualifies as a normal map.If the image meets these criteria, it is considered a normal map.

Creator tips

When creating a normal map, ensure that the colors accurately represent surface orientations.

Pay attention to the distribution of colors and adjust the texture accordingly.

Consider using software tools specifically designed for generating normal maps to achieve the desired effect.

Examples

value	valid	description
	✅	The image should be a normal map.
	❌	The image should be a normal map.