Using 3ds max, I'm just playing with a model, which I found from a game. I'm not familiar with 3ds max, Hopes the question is not so silly.

It has three types of maps, with 'D', 'N', 'S' suffix. So I guess D for diffuse, N for normal, and S for specular.

The first two seems right. but what's the type of the third one? It doesn't seem to be a specular map, but seems to be the 'metal' parts, so I tried using mix map but the result is also different from in-game result.

The following are the three maps, and my rendered result with in-game result. I think the biggest diffrence - the metallic small decorations, should be what the third map does.

‘D’ map ‘N’ map ‘S’ map 3dsmax rendered image in-game result

2 Answers 2


According to the naming conventions of texture files, the suffix _S is generally used for Specular Maps in Specular workflows, especially in the Unreal Engine (see e.g. here and here [updated version of first linked article - variations of this article are abound]), or for Smoothness Maps in Metalness workflows (see e.g. here).

What you have here is a Specular Color map: it defines the amount of specularity and its color in addition. You can see this in the gold embroidery, for example:

enter image description here enter image description here

The effect will be similar to this:


In Physically Based Rendering, this is only really physically correct when it is used to simulate metallic surfaces (so we can assume the embroidery is made of gold thread):

enter image description here source

This also implies that the rest of the map is either being 'cheated' on - as obviously not all coloured surfaces here are metals - or that the map is mixed with another map (which is not a far fetch since the 'normal' _N map seems to combine a regular tangent normal map with what could be a transparency map).


The S most typically would be smoothness - the inverse of a roughness map. Used often in a PBR metallic rendering workflow.

However, looking at your three maps, I don't think this is a smoothness map, or a specular amount map - but I think it might well be a specular colour map - makes the most sense based on your rendered output.

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