Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: MarsYellow on 2016-11-23, 03:21:36
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I am trying to create that blue glass in an interior scene and so far I had no luck my glass looks very fake.
basically the problems I am facing is the fact that all the light entering the room is going through the blue glass and that is a big problem for the following reasons :
-I tried using translucency to color the glass but that caused in a very strong color cast on the room and fixing that using white balance will cause in losing the glass blue color
-I tried denser blue color and that caused in having an unrealistic transparency and glowing effect .
- If I use rayswitch to exclude GI coloring the glass will look very fake it will look like if I added it using photoshop
-I tried using the diffuse to color the glass by reducing refraction and again that didn't look that good this method caused the lighting to dim and look bad but the good thing about this method is the very low color cast caused by the glass and the glass itself looks better than using translucency but it lacks the rich color.
-I tried to use tow Glass panels in front of each other one of them with diffuse method and the other with rayswitch in translucency to get a better coloring in the glass this method gave me the best result but not good enough .
any ideas ?
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First of all i would suggest you use the absorption Color for tinting the glas.
For further tweaking u could use a rayswitchmaterial to get control over the tint.
The problem is, that a room that is lit through blue windows will turn blue. Thats physically correct.
So every "solution" will be fake.
greetz
Lucutus
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Thanks for the respond
I keep telling my boss that the logical thing is the glass is going to cause the room to become blue but he didn't agree with me so i searched for an image using google to prove my point and the surprise was that it didn't color the room :D
looks like this kind of glass actually dims the day light a lot and after using it you will have to use interior lights to light the room so the results i am getting were not wrong after all they do look bad but they are not wrong :D
i guess the best way is the diffuse color way with a little white balance and then give the glass a richer blue in post to prevent using tow glass panels and increase render times a lot .
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Well in this example you have strong warmwhite interior lights and weak blue exterior light that is travelling in. If that scene would be in daylight with sun entering the room I'm quite sure it would color the room blueish.
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yes that is true ,but since my boss doesn't recognize that i will stick to the weak blue exterior light.Playing along is way easier than arguing forever ;D
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Haha, I can feel the vibe. ;)
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If your boss cant be persuaded i still suggest using the rayswitcher.
Use the tinted glas on direct, reflect and refract and use a clear (or less tinted) glas for the global ilumination slot.
This way u should have full control on how much the light in your room is tinted.
greetz
Lucutus
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I have just tried absorption with rayswitch and it actually looks really good .
one more question : since the glass dims the light a lot should i use portals even though the window is very big ?
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as far as i know Portals are only useful when the windows are very smal and there is just a small amont of light in the room.
Greetz
Lucutus
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Can somebody explain, for a similar situation (an office glass panel ), the difference between to use refraction color instead absorption color? Thank you.
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Refraction colour doesn't account for object thickness, it will attenuate colour in constant manner no matter how much thick or thin your object would be. On the other hand, absorption colour attenuates colour accordingly to distance that ray had travelled through glass object. If your model has varying thickness it will have richer or thiner colour in the end. In practice, use absorption to simulate coloured glass or use refraction colour to simulate thin coloured film applied to colourless glass.
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Thank you very much Romuluss!
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Even though I already knew what it means I enjoyed the explanation that was one smooth little explanation .
How would you explain the difference between absorption and Translucency ?
since the corona help article says that absorption is for objects that has no surface and Translucency is for objects that has surface shouldn't we use Translucency for colored glass ?
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Refraction colour doesn't account for object thickness, it will attenuate colour in constant manner no matter how much thick or thin your object would be. On the other hand, absorption colour attenuates colour accordingly to distance that ray had travelled through glass object. If your model has varying thickness it will have richer or thiner colour in the end. In practice, use absorption to simulate coloured glass or use refraction colour to simulate thin coloured film applied to colourless glass.
Very helpful and clear explanation. Thank you.
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since the corona help article says that absorption is for objects that has no surface and Translucency is for objects that has surface shouldn't we use Translucency for colored glass ?
Are you sure you didn't misinterpreted that article? Could you give a link to it? I can't imagine how object without surface should look :]
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Note the last line
""2. Corona Volume Material
Corona Volume Material doesn't require any special actions to enable scattering effects as it is designed solely for them. To see the effect of light absorption and scattering, simply change absorption distance value to other than 0 and scattering color to other than pure black. You can also make your material glow by changing "emission distance" to other than 0.This material should only be used for objects with no defined surface (smoke, clouds) and for volumetric fog. ""
https://coronarenderer.freshdesk.com/support/solutions/articles/5000534910-how-to-use-subsurface-scattering-volumetric-absorption-and-scattering-
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Ok wait looks like i have confused the volume setting in normal corona Material with the corona volume material that doesn't actually have any surface properties .But you should read the article any ways (if you haven't already ) it is a really good one . :)
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Yes, the Corona Volume mtl has no support for surface. It's only the volumetric effects.
Absorption and scattering can be also enabled for the standard Corona Mtl, and they work exactly the same way, but additionally you can enable effects on the surface, such as reflections, diffuse, ...
Absorption works in the volume only, but you can use it with surface effects too.
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Thanks for clearing that up
So why the two materials ,I mean wasn't it easier to put the light emission in the normal material and get rid of the volume material ? are there any advantages of using the volume material ?
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Thanks for clearing that up
So why the two materials ,I mean wasn't it easier to put the light emission in the normal material and get rid of the volume material ? are there any advantages of using the volume material ?
It's just faster and easier to set up for objects like clouds and for global volume.
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ok that makes sense