Specular or reflection map?

[AWBenson]

They are different things. An example of a specular effect is the white dot from a light source that is scene in a character's eye. The reflection map is to tell what is reflective or not and the amount of that reflectivity. In a realistic scene, you would use both and a great deal of other maps too.

Let's take an more detailed example. You built a low-polygon car model. It is entirely one object that is completely made of 1 polymesh and you UV mapped it to a single image file. However, on a real car the material would be different depending on what piece you are talking about. In particular, you have a bright shiny hood with metallic paint and you have dull, rubbery tires. Well, the paint reflects the area around it, so it would have some amount to the reflection map. The tire doesn't reflect it's environment, so that would be black (assuming that your software uses 100 reflect is pure white). The Specularity map would have an amount on the paint area. The tires would have specularity depending on their condition... if wet, then yes. If dry but has a white wall, then the white wall would have a low amount and the entire itself may look better with an extremely low amount.

I hope this helps some.

AWBenson

[lostlittleboy]

Thanks AWBenson, I was getting myself confused by assuming that more specular = more reflective...

[soulburn3d]

A specular reflection is just a reflection of a point light source. So if you want to use specular light on your car, adjust the specular map. If you want real raytraced reflections or an environment map, adjust the reflection map. So they are sort of both the same thing, a reflection, it's just they reflect different things.

Depending on which software you're using, make note that there are two things, a specularity map and a specular map, and a reflectivity map, and a reflection map. The difference being, reflectivity is a black and white map that defines how reflective a surface is. The reflection map is an environment map which is what the object should reflect. Some software combines both things into a single attribute, some split it into 2 to allow for more control. Here's a tut that may answer further questions...

http://www.neilblevins.com/cg_education/metal_and_refs/metal_and_refs.htm

This deals with 3dsmax, but the theory applies to all 3d apps.

- Neil

[lostlittleboy]

Thats exactly what I was after! Thanks for the info. :D

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