Sage, that's a pretty wrong answer :S
It all depends on the shader your engine is using. Most of them use normal mapping to influence both diffuse and specular contribution, so yes, it is worth it.
Some more advanced shader will even have an ambient contribution that take the normal map into account. Some other, such as the one in half-life2, will have lightmaps that use the NM information (that's also called "radiosity normal mapping").
Do you have moving lights in your scene? Does your object move?
If the answer to either of those questions is "yes," then normal mapping will definitely help, even without specularity.
If you have a non-moving object with a non-moving light source (for example, terrain lighted by a non-moving sun), and you aren't rendering specularity, then you could use baked-in lighting to get the same effect as normal mapping. (Of course, you'd probably want a normal map to bake from even if you aren't using it in your engine.)
But seriously... why aren't you using a specmap? Is it a shader/engine limitation?
thats true, you will have a plastic material if you use just that, or try also to make the gloss veeery low, maybe 2 to 4, but it will also emulate a "specular diffuse", so its not worthy
the real important question here is What material are you trying to represent?
Is it concrete/rock, materials that unless wet have very little reflective properties, in that case no, you dont need a spec map.
Is it metal? Well then hell yes you want a spec map, and posibly even a map for cube map reflection as well.
Study the world around you, observe materials and how they react with the environment, that should be able to answer most of your questions as to what does/doesn't need spec.
the real important question here is What material are you trying to represent?
Is it concrete/rock, materials that unless wet have very little reflective properties, in that case no, you dont need a spec map.
Is it metal? Well then hell yes you want a spec map, and posibly even a map for cube map reflection as well.
Study the world around you, observe materials and how they react with the environment, that should be able to answer most of your questions as to what does/doesn't need spec.
Brice are you saying that normal maps will look good without a spec map component? That's kind of how I took the question. Just diffuse and normal map affecting the diffuse no spec value. At any rate if that's the case it's good to know.
Sage, try it out and you'll see. Yes, for some things you can have just a diffuse and a normalmap, and it looks great.
Normalmap merely acts as a way to add detail to the surface curvature, so any lighting will show its effect... diffuse, diffuse cubemap, specular, reflection, refraction, etc.
thanks for the replies guys. here is what i'm workin on
it will be just a still shot or possibly be put into a whole scene in ut3.
as a still shot - the normal map does its job.
i didn't think i needed to make a spec for this material but i wasn't sure if it was vital component.
Cool asset. The normal map definitely helps. I'd say a spec map would be good if you wanted some of the surface to be a little bit shinier than the rest, like a lot of hands touched the bottoms of the trunk-pillars and left a cumulative darkening of hand-grease behind (which would also shine slightly).
it seems there's a bit of confusion between specular contribution and specular map. One is the effect that simulate specularity in a shader, the other is the ability to drive this effect intensity by a bitmap. Most answer have been given here already, but I thought it worth clarify this point. My answer was about having no specular contribution (a pure black specular map). Having the specular intensity approximate by a factor, a specific bitmap or using the difuse ( this would work for this particular asset if this is just about saving memory space) is just a matter of choice. btw Ryan Clark 's point (baking specular) is false in my opinion, because even if your scene is static the specular contribution is a heavily view dependent factor, that cannot be baked into a texture, unless it's a specific artistic choice (old schoolz )
You might try a specmap even though the object is not shiny... a small amount of specularity might look natural on smoother parts, such as the trunks and the floor. Not bright, mind you, just barely noticeable.
Specularity is a measure of the smoothness of your surface, on a microscopic level. Whenever part of your object is smoother than another, then a specmap might be useful, even if it's a very faint one.
well, for cloth only stuff i dont use specular maps , i mean it would be practically black, and why waste a draw call on something that would be almost black , for rocks etc, unless they are shiny or metals no need.
Anyone who devalues the use of specular maps should really check out what Epic does. It might be their specific art direction but they are a work of art, I almost think they spend more time on those then their diffuse maps, lol.
thanks for the replies guys. here is what i'm workin on
it will be just a still shot or possibly be put into a whole scene in ut3.
as a still shot - the normal map does its job.
i didn't think i needed to make a spec for this material but i wasn't sure if it was vital component.
Spec map can also be really useful for making the crevices pop more. A little contrast in the map will help the highs pop and the lows stay recessed. Taking your normal map into crazybump and doing an edge highlight pass helps with this stuff.
Replies
Alex
It all depends on the shader your engine is using. Most of them use normal mapping to influence both diffuse and specular contribution, so yes, it is worth it.
Some more advanced shader will even have an ambient contribution that take the normal map into account. Some other, such as the one in half-life2, will have lightmaps that use the NM information (that's also called "radiosity normal mapping").
Do you have moving lights in your scene? Does your object move?
If the answer to either of those questions is "yes," then normal mapping will definitely help, even without specularity.
If you have a non-moving object with a non-moving light source (for example, terrain lighted by a non-moving sun), and you aren't rendering specularity, then you could use baked-in lighting to get the same effect as normal mapping. (Of course, you'd probably want a normal map to bake from even if you aren't using it in your engine.)
But seriously... why aren't you using a specmap? Is it a shader/engine limitation?
Is it concrete/rock, materials that unless wet have very little reflective properties, in that case no, you dont need a spec map.
Is it metal? Well then hell yes you want a spec map, and posibly even a map for cube map reflection as well.
Study the world around you, observe materials and how they react with the environment, that should be able to answer most of your questions as to what does/doesn't need spec.
QFT!
Normalmap merely acts as a way to add detail to the surface curvature, so any lighting will show its effect... diffuse, diffuse cubemap, specular, reflection, refraction, etc.
it will be just a still shot or possibly be put into a whole scene in ut3.
as a still shot - the normal map does its job.
i didn't think i needed to make a spec for this material but i wasn't sure if it was vital component.
it seems there's a bit of confusion between specular contribution and specular map. One is the effect that simulate specularity in a shader, the other is the ability to drive this effect intensity by a bitmap. Most answer have been given here already, but I thought it worth clarify this point. My answer was about having no specular contribution (a pure black specular map). Having the specular intensity approximate by a factor, a specific bitmap or using the difuse ( this would work for this particular asset if this is just about saving memory space) is just a matter of choice. btw Ryan Clark 's point (baking specular) is false in my opinion, because even if your scene is static the specular contribution is a heavily view dependent factor, that cannot be baked into a texture, unless it's a specific artistic choice (old schoolz
cheers
(Specifically, I think you missed the word aren't)
@breakneck:
That piece looks very cool!
You might try a specmap even though the object is not shiny... a small amount of specularity might look natural on smoother parts, such as the trunks and the floor. Not bright, mind you, just barely noticeable.
Specularity is a measure of the smoothness of your surface, on a microscopic level. Whenever part of your object is smoother than another, then a specmap might be useful, even if it's a very faint one.
I think the back part tiles too obviously.