problem with the mia_ material_x

# 1 25-09-2008 , 04:46 AM

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I am working in an animation with just two glasses and a camera following a path to experiment with the mia_material_x (maya 2008). My problem is that when one glass is behind the other it became unrealistically dark and I don't know how to solve this without changing the black background color. I have tried a lot of parameters but I don't know how to do it.

animation

scene

Last edited by masbt; 25-09-2008 at 06:58 PM.

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# 2 25-09-2008 , 05:51 AM

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Try turning up refraction in the render settings in Mental ray

_J

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# 3 25-09-2008 , 06:59 PM

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It doesn't work.
thank you anyway.

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# 4 25-09-2008 , 07:42 PM

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I just looked at your scene, jeez dude, talk about complicate your scene. first use a spot light for the over head light with a nice penumbra for the falloff, this will make life a little easier other than that get rid of the other light start simple when it comes to lighting and add as you feel needded. I then noticed youve pasted the material from one glass to the next, just create a new mia x material and drag and drop onto the glasses, theres no need to copy and paste them, this could be half the problem too as mental ray can get a bit odd at times.

also having that black backdrop will certainly not help matters overall, but by using the one shader will cut down on your settings. Also switch on and off the raytraced shads on the light to get an idea of what settings in the render panel to crank up or down. I reshot your scene in 2 mins and it was fine for a test shot, just a few tweaks here and there to help it but other than that this made all the diffrence to the output.

Jay

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# 5 25-09-2008 , 10:33 PM

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Thank you for your time .
It doesn't matter if I change the lights, is allways the same. I have changed the pasted material (is the whole glass what was pasted), but is the same. Also I have played with the reflection and refractions in the mental ray settings but I keep getting this:

user added image

In other animation a ball pass behind the glass with the same effect, proof that the guilty is not the pasted material, but the look is not so unrealistic:

ball animation

I am beguining to think that perhaps it cant be done using this material. I dont know.

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# 6 25-09-2008 , 11:29 PM

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Heh, I beg to differ...

Jay

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# 7 25-09-2008 , 11:59 PM

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How did you do that?

Tell me, please

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# 8 26-09-2008 , 01:37 AM

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I agree with Jay there, I deleted your lights and used a spotlight and added a poly plane in the back with a gray surface shader. The problem was with your mia_material raytrace settings, you needed to boost the max trace depth in the advanced refraction section, otherwise you could have jacked up the raytrace render settings and nothing would have changed. Also the render settings were crazy for testing, that resolution was insane :x

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# 9 26-09-2008 , 01:48 AM

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Thanks Gen for the backup.

it can be achieved as well without the adjustment on that setting as its a physical shader but as with these things they can achieve some great results the more you play around with certain settings.

masbt: anyway I hope both these options helps you out. I just did all my render on a 640 x 480, one spotlight overhead and the same shader on both glasses, then hit the render button!!

Happy rendering

Jay

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# 10 26-09-2008 , 02:06 AM

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Another one for you, the back glass object has a dielectric shader on it. I chose the same angle as Gect because I thought by lowering the refraction setting for the front glass will show you the effect of widening the top of it

Jay

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# 11 26-09-2008 , 02:23 AM

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At last. This was the magic setting.

thank you very much.

I feel such a noob watching the GecT works...

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# 12 26-09-2008 , 03:20 AM

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I strike back

user added image

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# 13 26-09-2008 , 12:41 PM

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Thank you masbt user added image

Looks better, the highlights seem really strong though. The texture on the plane is really blurry, is it actually like that or is there filtering applied? Something was irking me about that glass shader so I went back and checked again, you had the transparency all the way up but it was still so dark. Then I realized it was just picking up too much of the dark grey floor in the reflections so I used fresnel reflections, even made another glass shader to compare and it was indeed the reflections.

Jay's test made me want to putz around with the dielectric shader, it looks good but how would you get rid of that grain? I always found that shader to be a little unfriendly, simple is good sometimes but for that reason I couldn't figure out the grain issue.

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