Specular Mapped Blinn DX shader

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Specular Mapped Blinn DX shader // The Garage

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Post by Jack Edwards // Feb 7, 2009, 4:57pm

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Here's an update for the Mapped Blinn shader. It now supports specular mapping. (and ambient mapping, and normal mapping, and alpha mapping...lol)
18101

You can see the thread for the old one here:
http://forums1.caligari.com/truespace/showthread.php?t=5893

Enjoy!

Post by kena // Feb 7, 2009, 6:43pm

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Thanks jack - I've downloaded this one too :D

Post by Jack Edwards // Feb 7, 2009, 7:05pm

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Welcome! :D

Meant to put this feature in the original but forgot... :o

Post by Nez // Feb 9, 2009, 12:13am

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Although I still can't use Workspace, it's very cool to see all these materials being developed and released.

However, when I finally can get stuck into Workspace/DX shaders, I am going to be somewhat lost due to all the new terminology - blinn, half lambert etc - what do all these things actually do/simulate?!


Is there (or can there be!) a simple 'dummies guide' thread somewhere that describes the main types of shader and what kind of materials you would use them to simulate? Please...! As a long term modelside/LW user, I'm used to using the full Phong reflectance shader for most materials, so I have no idea what any of these other shaders are useful for...! :o


Thanks...:D

Post by Jack Edwards // Feb 9, 2009, 5:57am

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Blinn is an improved phong that uses the Half-Vector to calculate the specular:
http://en.wikipedia.org/wiki/Blinn

Post by parva // Feb 9, 2009, 6:33am

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blinn, lambert, phong etc


family names from (mostly) mathematicians that created a function to describe how surfaces reflecting and refracting light.

Some of them base upon empirical others on physical models. Empirical is mostly faster to calculate.


Blinn isn't really an improvement more like a cheaper (cheap means in amount of calculations) version and not as accurate as Phong Shading (but even Phong isn't "accurate" at all).


You can find stuff all over the inet.

Just search for BRDF models like this one (http://www.irrlicht3d.org/papers/BrdfModelle.pdf) (german)

Post by Nez // Feb 9, 2009, 6:51am

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Blinn is an improved phong that uses the Half-Vector to calculate the specular:



Well, gee, that all makes sense now! :rolleyes::D


Doesn't change the fact that I'd like to see a (simple) list of the main shader types and when is a good time to use them... (or when something else would be better). Not a major panic yet as LW is familiar territory, but all these fancy shaders that keep cropping up are frankly scary...:o

Post by TomG // Feb 9, 2009, 7:09am

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Did you know there are no such things as specular highlights? They are, in the real world, all reflections. But the specular highlight is a quick "cheat" to save on having to get into raytracing to calculate reflections (and to save on having to model the light source in order to reflect it of course).


The different names of shaders all have different ways of "cheating" to simulate surfaces, since the real way of doing it is very computationally expensive (that's where you move into GI territory).


A quick summary of which shaders are great at "cheating" on which materials / situations could be interesting.


HTH,

Tom

Post by GraySho // Feb 9, 2009, 11:07am

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On a sidenote: To be precise everything you see is "reflection" of light or the lack of reflecting certain light colors/wavelengths that define the aspect and color of every object ;) Not that I claim to be an expert, but as we are talking about it....


Nice contribution Jack, I´m sure I´ll have some use for it.

Post by Nez // Feb 9, 2009, 11:42pm

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Did you know there are no such things as specular highlights? They are, in the real world, all reflections.


I found this out relatively recently when following the excellent HDRI video tutorials and understand it is why you shouldn't normally try to use specularity in your shader settings when using HDRI - as a result I'm still trying to get to grips with good shader settings for different materials when using HDRI, as they can be quite different from the settings I was using in tS5...



A quick summary of which shaders are great at "cheating" on which materials / situations could be interesting.



Definitely would find this useful - I appreciate it's quite complex as it depends somewhat on the render engine and lighting - as above, settings different if using HDRI, guess best reflectance shaders could be different again for VRay, real time etc but a 'dummies guide' would be great - or just a thread (or threads) where people share good sample materials or settings for the main render engines available...

Post by parva // Feb 10, 2009, 12:12am

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Phong / Blinn-Phong comparison

18152


It's often said that Blinn-Phong match measured data more accurately but if I see the rim-lighting I doubt that.

Of course can't compare there I don't have the possibilites to compare with real world conditions :D


The specular point is a bit smoother and larger but rim-lighting don't bulge with the surface

Post by Jack Edwards // Feb 10, 2009, 5:58am

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You can't really see the benefits of the Blinn model on a sphere, with more complex geometry the blinn specular with "stretch out" toward the view as the angle of the face becomes more perpendicular with the view. The phong model on the other hand doesn't take the eye direction into account.
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