Specularity map - eccentricity or roll off?
 

Hi,

when you create a specularity map, is it more properly mapped to the material's eccentricity or roll off node?

cheers,

gubar

You should map the specularity to the roll off, but also to get a good spec you should invert the spec map and apply it to the diffuse also, since diffuse effects how much a material relects light.

i always map the spec map to the spec color - is that wrong then?

Hi,

after trying all 3 today, I've actually found that I prefer it applied to the eccentricity. It gives me a look that is closest to my photo reference.

gubar

No it's not wrong that is actually what I ment, and some ppl map to eccentricity but that is something different but reading up on the subject from many sources and the most common recomendations say to create realism you need to map the spec colour and diffuse.

Hi jsprogg,

rereading my last post, sorry I never thanked you for your contribution.

I've got the diffuse map too, and I have since read that many people map the roll off (and not the eccentricity). In the case of my objects, I just find mapping the eccentricity looks better - guess you just go with what is working the best.

cheers,

gubar

yeah - i've been having a play and mapping to diffuse and roll off works well - though on a couple of objects eccentricity worked good. do you use the same map?

The diffuse map is usually less value and from what I have read it recomends inverting the spec map.

specularity is a really a fake since it's not actually relecting light and is used to simulate reflectiveness ,where as reflectivity is the real deal and is actually relecting light .
The main difference between them in a 3d package rendertime, since specularity or specular colour is not actually relecting but just changing the colour of the surface to simlate relecting light there is no calculation to be done so therefore a lot quicker to render.

cheers jsprogg - yeah - i've read similar but guess i haven't really done enough experimenting.:)

do you invert the spec map on the diffuse or roll off?

invert the spec map that you would use on the specular colour and apply the inverted map to the diffuse.

got you - thanks mate ;)

Hi,

arran, I've used the same map but tweaked the one for diffuse to make it brighter.

Jsprogg are you sure it should be a lower value? I find that gives me a dark surface with bright highlights... which would be good for some surface I guess. Would depend on the material I suppose.

Also, are you sure you should invert it? What you would get in that case would be dark areas with bright highlights, and bright areas with less highlights.

cheers,

gubar

It should be lighter , so when I say lower value I am talking in the greyscale sense in which more value is darker.
I am not certain it should be inverted but when I was reading up on it thats what it said, i guess if inverting it makes it lighter then yes.
the way it works as a general rule is the lower the diffuse setting the more reflective someting is noe in Maya I don't remember if that translates to lighter or darker in the diffuse channel.