UDK Gloss map HELP

manilamerc · Sep 2014

Okay so I have this wall where I only want one thing glossed up which is the outer part rim around the door. when I put the gloss map in 3ds max it works fine but when I try putting it in UDK the whole wall becomes glossed up. I was following a tutorial but did not get what I wanted.

So this is my diff and gloss map

this is my UDK settings for the maps

This is what the mesh looks like in the engine

JedTheKrampus · Sep 2014

Since you hooked your map up to specular power, it's a specular power map in this case, rather than a gloss map. In UDK, specular power determines the size of the specular highlight, while specular (aka specular color) determines the color and intensity of the specular highlight. You can get a good feel for the numbers you'll want to put into specular power by making a simple sphere and putting a material on it that puts a color into diffuse, a color into specularity, and a number into specular power. I don't have UDK installed, but the documentation says that it uses the Phong model to light things, so I can provide examples from Blender's Phong implementation.

Here's a gray sphere with a bright specular highlight. You can see in the material properties that I've provided a specular color of 100% white (i.e. 1, 1, 1) and a specular power of 32.

Let's see what happens when I increase spec power. This number can really go quite high, depending on how tight you need your highlights to be.

As you can see, the highlight retains the same intensity but becomes much smaller. What if I take specular power down to its absolute minimum?

As you can see, when you take specular power all the way down to black, you get highlights the size of a Buick. This can be warranted for very rough surfaces: you should technically always have specularity on a surface, and if it's something rough like stone you should have a low specular power and a correspondingly low specular intensity.

When you put in your gloss map into the UDK material, it's looking at that specular power and saying, "OK, these parts of the specular power map are black, so I need to make the highlights really, really wide here." If you want to have such wide specular highlights (which would make sense for the material your walls are made out of), you need to tone down the specular color map in those areas where the specular power map is that dark.

almighty_gir · Sep 2014

do a linear interpolate node, plug a constant value of 0 into A, a constant value of 256 into B, and plug your gloss map into the alpha of the lerp node. plug the result into specular power.

passerby · Sep 2014

what gir said, UDK dosnt take gloss values in a 0 to 1 range, so you use the lerp map the texture that only stores 0 to 1 values, to 0 to 256 values.

also you can adjust the A and B inputs of the lerp later to fine tune your look

King Mango · Sep 2014

What's happening is that when you plug your mask into the specular power you have a bunch of black so no matter how much you multiply it, it will still be zero so you will get super gloss in those uvs that fall in the black of the texture space. Try adding a float to your spec power mask to get those values working for you. Clamp it if you don't want it to affect your white spot. Then get your white bit to the spec you want and change the value of your add to tweak the rest of the values.

UDK Gloss map HELP

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