View Full Version : mia material as clearcoat

06 June 2010, 08:22 PM
its my first time to use mia material as clear coat in car paint, it was really great but theres a strong hot spots , i mean the highlight is so strong. is there a way to minimize it in mia setting? im using maya 2009.

06 June 2010, 10:16 PM
Determine if its a reflection problem or a specular problem.

If its specular issue (reflection of your cg lights), then you can reduce or even eliminate altogether the specular effect by lowering the Specular Balance attribute in the mia_material (its under advanced rollout).

if its a normal reflection issue, you'll have to play around with your reflection intensity and/or the BRDF function.

In my experience however, using layered shaders will break the physical correctness of the reflection because it will not be subtractive anymore, which will leave your reflections looking kinda milky..

07 July 2010, 12:03 AM
yes, after testing and experimenting with the layering for clearcoat seem im not getting the right glossiness.

07 July 2010, 09:58 PM

What's your approach to a clearcoat then? How do you use a layered shader (mib_mix8 etc) in a physically correct way? Have the blending mode of each layer set to "add" and have the sum of their weight=1?

07 July 2010, 08:59 AM
Try it a different way round. I use a mia using this to set the glossy metallic reflections using c]]glossy reflections and difuse, then plug in a car paint material to the mia's additional colour and use the car paint for the clear coat and the metallic flakes. Works really well but will take more tweaking to get a correct look as you lose your light conserving ability of just using the mia

07 July 2010, 01:20 AM
I was at siggraph 2007 and watching the making of transformer. i was suprised on how they have approach the car shaders which they have way too many nodes connections. (though they didnt elaborate the shaders)so i was asking myself that time is it that really hard to get the right shader for the car paint?

ive tried zaps way on blending two shaders (which is good) but im aiming for different approach,
and also im not having correct fresnel reflection with mia which im having this strong light reflection on the edge and might try the old method. Ive been observing car paints lately and i was impressed with a certain metallic paint which the flakes is much finer and the glossiness is much obvious.(and also the irradiance) and thats what im aiming for. still experimenting.

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07 July 2010, 01:20 AM
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