"spec" is short for "specular". These textures (and bump - bumpmap) were introduced into FSX to give more visual fidelity. Basically, your "normal" paint (it's called the diffuse map) is the colour scheme texture with its alpha channel. The better models these days tend to leave the 3D model not so shiny and reflective and the alpha channel governs the shininess.The specular map tells the sim engine how the light is reflected off the surface. If you look a car in a showroom, it's usually in pristine white light so that you get the "real" visual experience. Imagine that car is now moved under yellow sodium streetlights - it will look totally different. The specular then, is how the surface takes the colour of the ambient lighting and alters it so that the reflected light is more real.If you have been painting a while and have something like Photoshop, you will find a colour wheel. The "normal" (original FSX) method of creating a specular is to take the diffuse map image and "rotate" it 180 degrees, reduce saturation and increase brightness. (the actual values are practice and experience, because models have been made with different values fixed on the 3D model) - just look at some of the FSX default aircraft and you will see what I mean - ACES standard is 180° rotation with something like -50% on saturation and +50% on brightness.When you are actually flying in sim, the reflected light also depends on the angle of the sunlight to the painted surface so as you pan around in outside view, the colours will appear to shift in accordance with how you make the spec...Specs hav alpha channels too - and again, how these affect the model also depend on how the modeller has defined the 3D mdl. A light, low contrast greyscale is the norm here.As you are working on the Carenado
model, you will see that their specs are more sepia toned. Carenado
also use a fully detailed texture for their spec. You can use just the fuselage parts and leave all the detail bits like engine, tyres, glazing blank spec and black alpha and you don't absolutely need to specularise the dirt and shading.Normally, you will have to create a new spec for every paint. If only because the original aircraft registration will show through if you don't. But like I said, all you need do is take a copy of your final diffuse map dds, open it in DXTBmp. Then you just send the image and alpha respectively to your editor and adjust the two parts of the image as I describe. SAVE AS THE SPEC name and do not save as-is.Of course... if you want metallic effects, or that wonderful "flip-flop" two colour paint effect (i.e. along the lines of the car in the film Triple X) then here you can use the specular map to do similar things. But the "howto" is another, looong story that involves noise, different rotations, detail work on the alphas... It's no trade secret, but it does take a lot more practice.Here are a couple of external linked thumbnails showing just some of these specular effects (I don't want to blow the forum with over-large pics) - just click the thumbnail1. a polished aluminium metal paint. The spec on this one is into the blues to give that extra deep sky reflection
2. the Viper paintscheme uses a flip flop green for the snake scales pattern - if you look at the fuselage, you can see that the green scales on the side look blueish - that is becaus the green parts of the diffuse are bright blue in the spec.
3. This little "freestyle" painted Bede is using "noise" on the spec to create the metallic effect.
4. Here's another, closer look at metallic using the alpha channel and noise...
5. This image to show how the colour of the spec can affect the diffuse map. Without the spec this "gold" would be just a shiny yellow ochre colour. With the spec tuned to reddish, you also get a slight "flip flop" colour effect when the light is right.
and finally - here's what happens if you keep the original spec and just paint only the diffuse (an orange skin using the Patty Wagstaff specular) - so you can even use spec to play around with "secret" advertising...