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Reflection - Controlling
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Reflection - Controlling // New Users
Post by jamesmc // Feb 21, 2007, 5:52am
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jamesmc
Total Posts: 2566
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Trying to figure out how to control reflection to keep it to a minimum.
I have turned down reflection and refraction in the material editor, but still get the reflection.
Any thoughts how to get rid of this reflection? It's nice, but don't want it to be that big and it distracts from the clarity of the object. |
Post by Bobbins // Feb 21, 2007, 6:02am
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Bobbins
Total Posts: 506
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From your image I'm pretty certain that it is refraction and not reflection you are seeing. If you lower the transmission parameter in the reflectance shader on the objects you can minimise it, but that could also have an adverse effect on the look of the bottles.
You can also try lowering the Max.Depth. setting in the RayTrace Options panel: a value of 2, 3 or 4 should cut them out, but again might have adverse effects on other parts of the scene. |
Post by TomG // Feb 21, 2007, 7:17am
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TomG
Total Posts: 3397
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Yep, that's transmission by the look of it. The only thing to do is turn down the Transmission level, but then of course you are making your bottles less "see through". However, that's the only way to stop you seeing the labels and grid through the bottles, by making them less transparent in that way.
Things that might help - the transmissions show up so strong because they are the only things being seen through the bottles. The rest is grey nothingness. If there was a ground, wall, sky, etc, then the rest of the bottles would not be grey, but would also have something to see while looking through them, making the labels etc less intense.
Shadows would help. The labels behind the bottles would not be so brightly lit then, and so would not be so bright when seen through the bottles.
Both the above are about the "realism" of the scene set up.
To artificially control it, masks and layers in Photoshop could work. tS7 or iPak would let you separate the transmission channel out to a separate layer for adjusting strength (with the plus that you can mask that layer, so keeping the grey strong, but darkening the layer or reducing the transmission layer blend where the transmissions are bright).
You can make your own masks for this purpose, either just render once and edit to darken those areas, or you can do multiple render passes (change the material to only transmission, render; only reflection, render; solid black to act as a mask, render; specular highlight, render; diffuse, render - or combining those where you dont want separate control).
You might want to check if the objects are double sided too, and if they have "depth" to the glass. Ensuring they render double sided will give more glass surfaces for the ray to pass through, ensuring things blend and darken a little more before escaping one bottle object altogether and hitting the others.
Giving the glass a darker color (other than white) might help too.
Using a Fresnel shader might help as well as then the transmission (and reflection) of the glass can realistically vary with angle, giving a less uniform look to the transmissions and perhaps breaking it up a little and making it less dominant.
Lots of ideas there, hopefully something will help :)
Tom |
Post by jamesmc // Feb 21, 2007, 10:29am
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jamesmc
Total Posts: 2566
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I think some of Tom's suggestions are working out. This is some free work I'm doing for some advertisement for an attraction. (To get people to go into the saloon to buy cold water or drinks.) :)
What I did is not to further smooth subdivide the bottles and used a different glass shader which had less tendency to er refract?
Now I need to add some droplets on the bottles to show these are cold.
Not sure if I should do this in a paint program or try to use tS to make droplets.
...we'll see how it comes out.
Thanks for the help! |
Post by GraySho // Feb 21, 2007, 10:56am
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GraySho
Total Posts: 695
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If you want some realism, you need transparency, and with transparency you'll see the background objects. Make sure you have the refraction set right. Different materials have different refraction values, meaning the amount the light is bent when it's entering or leaving the material is different. Water for example has a refraction of 1.33, glass around 1.5, plastic from 1.45 to 1.55. Just enter these number into refraction channel (right click for numerical input). You find a more complete table here: http://www.robinwood.com/Catalog/Technical/Gen3DTuts/Gen3DPages/RefractionIndexList.html
I recommend you model the water in the bottle as a seperate object and give it it's appropriate refraction. I would also model a flat water drop and distribute it over the bottle's surface. |
Post by jamesmc // Feb 21, 2007, 7:24pm
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jamesmc
Total Posts: 2566
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If you want some realism, you need transparency, and with transparency you'll see the background objects. Make sure you have the refraction set right. Different materials have different refraction values, meaning the amount the light is bent when it's entering or leaving the material is different. Water for example has a refraction of 1.33, glass around 1.5, plastic from 1.45 to 1.55. Just enter these number into refraction channel (right click for numerical input). You find a more complete table here: http://www.robinwood.com/Catalog/Technical/Gen3DTuts/Gen3DPages/RefractionIndexList.html
I recommend you model the water in the bottle as a seperate object and give it it's appropriate refraction. I would also model a flat water drop and distribute it over the bottle's surface.
I tried this and can't see to tell the difference when refraction is changed.
Maybe its a thing with lightworks not sure.
The one thing the refraction from the table did do is reduced the amount of images refracted into the surface of the transparent object.
That's one problem solved, thank you!
So, that's one goal. The transparency difference (if there is any) may be my visual acuity as I can only focus with my left eye. heh |
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