Join Adam Crespi for an in-depth discussion in this video Using diffuse layers as a basis for specular maps, part of Learning to Texture for Games.
One of the most important components in the texture is actually the Specular Component. We need our Specular Map, to do things like make the rust dull and the metal shiny where it's still in pretty decent shape. We can also use that specular wrap to add in scratches on the floor here and make this metal grating really pop out. Right now we are seeing just the raw diffuse color. It's unlit or flat lit in Maya. And it's not a good way to judge how this is going to look when it shines. We are using a Blinn material and this is a next-gen material for games, so it's a good simulation to use and test out what we are doing.
I have broken the transparency by right-clicking on the word Transparency and choosing Break Connection. Maya puts it in automatically if there's an Alpha Channel and a PSD. But we don't want transparent metal walls. I'll demonstrate how the specular highlight looks at the moment by putting a light in. It's a good idea to do this; not just looking in the viewport, but actually putting a light in by choosing Create>Lights>Point Light. We will put a point light in, move it up in the corridor, spin around to be able to see it and press F to focus. Now with this light in place, I will turn on High quality display and press 7 to show the lighting in the view.
When I go into the corridor, we can see it's all very even, that is I pulled this light up and down, we can see the shine change a little bit, but everything is the same just the light value changes. Pulling the light close to the wall doesn't show any extra shine here in the gray metal and doesn't show any glimmering highlights in the rust or on the screws I have added. We can see that and we need to define how this looks and we will go back to Photoshop to do it. One more thing before we dash back to Photoshop. I am back out in my scene and I will press 6 to go back to shaded and get out of High quality display for a minute.
I've done a quick test here with my modules, taking the three frames and putting them together to make the basis of a T intersection. I need a couple extra polys here, these triangular corners and I can use two of my existing floor polygons and wall polygons to close this off. We want to think in this way. If we need extra pieces, can we take what we have and put it on an existing sheet? Here is a quick trick to make this work. I'll take a wall, press Ctrl+D to duplicate and slide this over. We can see here, holding V for snap, that it doesn't quite line up and finish out how the intersections should be.
When I turn on Wireframe on shaded, we can see a gap there. And simply cloning it over will leave polygons hanging off the edge. I will press and hold W and left click anywhere and bring up the marking menu for move, and I will turn on Preserve UVs. Now with that on, I'm going to craft a new poly and slide it over and keep the UVs as they are instead of stretching them. I will press F9 for Vertex, select these vertices and snap them onto the existing wall. When we spin around, we can see I have started to go on to part of the frame and so now I will pull these back halfway.
I think these are about 250 wide, so I am going to slide it over to let's say about there. Now I will take this object, duplicate it by pressing Ctrl+D, V for snap and snap it over onto itself. When I turn off Wireframe on shaded, I have a reasonable juncture here. Yes the screws are off a little bit and that's okay, it adds a character to it with the panel sort of in the middle here and a joint accommodating the difference in rust. This helps to finish out that intersection and preserving UVs allows me to slide those words around without stretching out that texture.
I'll make sure that my panel is snapped in, so it's light-tight, pressing F9 for Vertex, V for snap and snapping it over. What this lets us do is build up our kit of parts, taking pieces we already have on texture sheets we already have, making new parts and unwrapping as we go. Now I will go in to Photoshop and work in the Specular Map. Here in Photoshop, I have got my PSD up. And right now I'm working the spaceparts color layer set. I am going to use some of the pieces from this to make that specular map, and the most obvious at the moment is the rust. Where the metal is clean, it should be shiny and where it's rusty, it should dull down.
I'll take this Rust layer and select it and clone it then drag it into that other group. There is rust copy and now I can take it and pull it down into that specular layer set. I will put it into the specular rolloff above layer 1. In this rust then, I can define where is it shiny or not. I also need in here a color in this specular rolloff because we can see layer 1 is blank and that's why we are getting those errors in Maya. Here is how I will start to make this specular layer set. First I will roll up color and turn it off.
There are the Specular layers at the moment. I will go in to layer 1, press Shift+F5 and fill it with a 50% gray, that way it's neutral, neither shiny nor dull and I have range up and down here into white and black to craft my specular highlights. Then I will take my Rust copy and press Ctrl+Shift+U to desaturate it. Already this would give me some variety. Just by saving this and update the PSD, we will see that I have shiny metal in the middle and dull here in the rust. I'd like to add to it as well though. I'll go back into the Color group, scroll down and find the holes in the floor.
I will take them hold Alt, clone them down into the specular rolloff and then also go find the grain. It's in here somewhere, called Brush. Again, I'll Alt+clone it down and into that that other group. What I start with a lot of times then for my specular layers is simply a clone of the diffuse made gray. I'll take this brushed copy and desaturate it Ctrl+Shift+U again. I'll do the same with the holes making sure that I've got black here. And then I'm going to go into the levels and pull that all the way down to black, choosing Image>Adjustments>Levels.
It doesn't look like much because I have got a tiny little blip here in gray and black because of the way I constructed it. What I can do though is pull this down, either making it a little shiny or little duller depending on what I'd like, pushing that mid gray around for example and making the space between the holes brighter. Leaving the holes dark will give me a center panel that looks a little bit shinier, then I will pull the black level up and make sure those holes are nice and deep. By pushing these two together I can get a really different specular highlight going. I will use my levels on the brushing as well.
And I will zoom in to see how this looks. Right now this is an Overlay layer and it's fairly muted on that specular highlight. I am going to turn this over to a Screen to really make it pop out here, but then I will put it may be under the holes and see how that looks. We also have the advantage here in our layers of moving things around little bit. On second thought, I think I would like to have it be brushed there, on top and that way it's two different tones of metal with brushing over them and the holes in there. I'll play with my layers and also work on the color or density of this map a little bit, choosing Image>Adjustments >Levels again and pulling this value around on the brushing, so that the holes retain their depth and the brush panels pop out on the sides.
Now the last part to it then is I am going to take the black and the holes and subtract it from the brushing. So I don't have brushed darkness. On the holes layer, turning off brushing temporarily, I will press W for 1, make sure Contiguous is off and my Tolerance is nice and low. I will Magic Wand the black, go over to the brushed copy layer and delete, pressing Ctrl+D afterwards to deselect. Now I have got a good specular map for the floor where the shine is going to vary all the way across. I will pull in other layers and see how it looks, but first I'll save this map and go test it in Maya.
Back here in Maya, I have updated my PSD, so I am using the right images and have all the right components. I've still got my light in place and I will go in the High quality and make sure I press 7 to show the lighting. When I do that and move the light around, I can definitely see a change on the walls. We can really see where that rust is dull and the wall between is shiny, watching the specular highlight travel and the intensity change. We've also got a good travel going on the floor where the specular highlight changes ever so slightly on the holes versus the frame outside. We can keep going with our specular work, making sure things really pop out here and bringing up the intensity of that highlight by making the values lighter.
To make things really pop out, I'll paint in a little bit of white. For example I would like a little bit more specular highlight right here on the wall. I will go in layer 1, put a new layer over it, press D for default, X to flop colors, B for brush and upsize my brush a little bit. This is a big soft brush and I'm going to paint my specular highlights in a linear dodge or add at a very, very low opacity; 5% is almost too much. I will just start to add in, oops, that's too hard, a little bit of soft brushing right here in the middle of that panel.
And this is going to bring out a little bit of shine under it, add blows out to white very quick, so little a bit goes a long way, but now it would be nice and shiny in the middle. I will do the same here on these panels, just adding in a little extra shine here and there and a little bit on the doors. This is why we deal with a 50% gray in specular highlights, so that as we paint we've got range up and down. I can have dull dark rust and bright walls where they are well, hopefully not as rusty. I'll save this and go update the texture in Maya and check it out one more time.
Here in Maya then, once I have got that PSD set, I can choose texturing and update PSD networks and I will see a difference. Now when I take this light and pull it close, once the PSD network is updated, I will start to see how that highlight changes. We are close to the wall and I can see as I pull this light around, the highlight spreads out and concentrates and spreads out again. I can really make this pop out and once I get a Bump or Normal in, it will really start to shine nicely.
- Introducing texture tiling
- Stacking polygons in an unwrap
- Establishing base colors
- Establishing realism with age and wear
- Cleaning up seams and joints in textures
- Creating dents and scratches
- Working with normal maps
- Sculpting detail
- Baking occlusion for rust and dirt
- Working with value and color for incandescence
- Faking reflection
- Painting skyboxes