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tehrobster2's Avatar
Old (#1)
So I was wondering if anyone knew any good links to articles on Gloss maps or could tell me the difference between a spec and gloss map? From what I have read so far, a gloss map is mostly used for metal or plastic. But how is different is a gloss map supposed to look apposed to a specular? And help would be greatly appreciated =).
Offline , triangle, 299 Posts, Join Date Feb 2010,  
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imperator_dk's Avatar
Old (#2)
A gloss map defines the size of the specular highlight per pixel also called specular power, where as a a typical specular map defines the intensity per pixel meaning it represents the amount of light reflected.
Offline , spline, 100 Posts, Join Date Mar 2009, Location Copenhagen  
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JacqueChoi's Avatar
Old (#3)
Black white and grey are your friends.

This is a good way to debug a shader Create a sphere:

Put a Black Specular, and a 50% Grey Gloss See what happens.
Change the Specular with the Grey Map, and see what happens.
Change the Specular with the White Map, and see what happens.

Notice the difference?

Now put the Specular at 50% Grey.
Change the Gloss with the Black Map, and see what happens.
Change the Gloss with the Grey Map, and see what happens.
Change the Gloss with the White Map, and see what happens.



Despite any dictionary definitions anyone might give you. You probably won't really understand it unless you do it for yourself.


Jacque Choi
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Eidos Montreal - Deus Ex
Offline , veteran polycounter, 2,606 Posts, Join Date Aug 2006, Location Montreal QC, Canada Send a message via MSN to JacqueChoi  
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tehrobster2's Avatar
Old (#4)
Hey guys thanks! I am going to start practicing right away!
Offline , triangle, 299 Posts, Join Date Feb 2010,  
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knak47's Avatar
Old (#5)
So with an engine like UDK are people generally making gloss maps for there shaders? Or is it more common with next-gen consol games to just plug in a constant into the specular power input?
Offline , spline, 175 Posts, Join Date Jul 2010, Location Seattle, Wa  
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Jon W's Avatar
Old (#6)
Is there a hard and fast rule about the size of the specular highlight with regards to material types? So for instance, a polished pool ball will have a tighter highlight, and a slightly matte old, painted metal will have a larger one?
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Offline , triangle, 475 Posts, Join Date Jan 2011, Location UK  
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vargatom's Avatar
Old (#7)
Generally the smoother the surface, the smaller and sharper and stronger the highlight should be.

Keep in mind that specular is a cheat and it's easy to mess it up. Best thing you can do is to ask the coders to write a physically correct, energy conserving shader.
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kodde's Avatar
Old (#8)
Quote:
Originally Posted by vargatom View Post
Keep in mind that specular is a cheat and it's easy to mess it up. Best thing you can do is to ask the coders to write a physically correct, energy conserving shader.
You mean like the TGA PBL shader? ;)
Oh, and I'd not refer to any real-time shader or offline shader for that matter as "physically correct", "physically based" is a better term.
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Computron's Avatar
Old (#9)
What about in UDK? What type of shader is commonly used there for AAA 360 level graphics like say Gears 3?
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tehrobster2's Avatar
Old (#10)
Sorry one more question, where would you plug in the gloss in Maya or UDK =) ??
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kodde's Avatar
Old (#11)
In your specular gloss/roughness input parameter. Some shaders might pack this data into one of the other textures, such as the alpha channel of the specular texture.

If you aim to get this visibile in the Maya viewport I'd have a look at using a CGFX/HLSL shader instead of the Maya default materials as they usually allow you to tweak more features than is possible with the default ones.
http://wiki.polycount.com/CategoryShaders
Offline , dedicated polycounter, 1,420 Posts, Join Date Dec 2004, Location Malmö, Sweden  
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tehrobster2's Avatar
Old (#12)
Okay thanks a lot my friend that was a lot of help! =)
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passerby's Avatar
Old (#13)
Quote:
Originally Posted by tehrobster2 View Post
Sorry one more question, where would you plug in the gloss in Maya or UDK =) ??
in maya you will need to get a hlsl, or cgfx shader like kodde said in UDK Gloss is 1 of your parameter inputs, it's just not called gloss, so just look for specular exponent.

because this input expect above 1 values, you will need to eiahter multply your map a few times, or plug your map into a linear interpolate node and plug constants into it's other inputs.
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kodde's Avatar
Old (#14)
Could be worth mentioning, but they Blinn and Phong shaders in Maya do have attributes that control similar features as gloss do. So it is possible to get similar results in this case. My suggestion with CGFX/HLSL was more in general if you want to get more game like results and relate your work to real game productions.
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tehrobster2's Avatar
Old (#15)
Hey thank you again to both of you guys I am defentiely going to try the cgfx shader first and then I will try Udk. But I am going to start out in Maya, so I can play around with the gloss map and see the different effects that I can get.
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Ehsan Gamer's Avatar
Old (#16)
I wonder what is the pipeline of getting a spec and gloss map in Photoshop .

I mean is there a tutorial for that ? Or is there any suggestion ?
Offline , spline, 141 Posts, Join Date Aug 2011, Location Tehran / IRAN  
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sebas's Avatar
Old (#17)
Here's a few but very useful examples/tutorials using Gloss maps:
http://www.philipk.net/tutorials/mat...materials.html

Hope it helps.
Offline , spline, 244 Posts, Join Date Apr 2007, Location Spain  
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Ehsan Gamer's Avatar
Old (#18)
Thanks sebas .

I will make a topic of mu progress soon .
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