View Full Version : Gloss (Spec Power) Not working
09-13-2010, 06:27 PM
Every time I try to do anything with the specular power slot in the UDK material editor my model turns black or I get very bizzare shading. I tried a dark image, a light image, simply using and adjusting a constant and its always messed up.
Are there any examples of propper use of spec power or anything I need to know that's specific to UDK?
My gloss setup works fine in max with the 3point shader.
09-13-2010, 06:40 PM
I might be able to help - Could I see a screenshot of your shader setup in UE3?
09-13-2010, 06:48 PM
sounds like you're plugging a texture in, textures "typically" go from 0-1 Specular power is a value that goes from 1-100+ usually. Either add and multiply the texture by scalar values, or use the specular power textures as the alpha of a lerp between 2 values.
09-13-2010, 07:24 PM
That's what I have thanks to JordanW. However, in the 3point shader it appeared as though I could have a colored glossmap that would affect the color of the specular falloff. This isn't possible in Unreal is it?
09-13-2010, 09:02 PM
I haven't used the 3 Point shader, I know what a shame :(
But you can get color in your specular, just plug an RGB map into the Specular slot.
Or are you talking about having one color for your specular highlight and another for your specular falloff? If that's the case I think you'd need two RGB maps and/or a way to shift the hue based on camera (or some other) vector.
09-13-2010, 10:50 PM
yeah I was talking about having two separate colors, but really its not that necessary. This should work for what I need to do. I just wanted to make sure I was understanding things correctly.
As you can see from my pic I already have an RGB image in the spec slot.
Anways thanks a bunch for all the help everyone! Polycount wins again :)
09-18-2010, 04:24 PM
Jordan is there a way to use a spec map as spec power without using a LERP? I would like to adjust the spec power on different surfaces on the object. I do this now through using a LERP. I was just curious if there is another way. It's too bad there is not a way to allow a greyscale texture to fall in the 1-100 range.
09-18-2010, 05:27 PM
I mean any mathmatical way you can create higher values than 0-1 will work. A lerp is the best solution because it's 1 instruction on the GFX card (Mult+Add). You can get more complex results by using fresnel to modify your specular power but a lerp is pretty much the bread and butter of mixing values.
09-18-2010, 06:16 PM
Yeah LERP is what I've been using for a while to get different spec power values on 1 material. Using the fresnel sounds pretty interesting. I'll have to try that sometime. Thanks man!
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