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What’s with this reflection problem
Posted: 23 August 2012 12:01 PM   [ Ignore ]
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I don’t understand why this keeps doing this. I want to bounce a light off a mirror like surface but instead this happens.

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Posted: 23 August 2012 12:14 PM   [ Ignore ]   [ # 1 ]
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Increase the number of raytrace bounces in the rendering setup. (I don’t have a copy of Carrara at work, so I am misnaming things)

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Posted: 23 August 2012 12:47 PM   [ Ignore ]   [ # 2 ]
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Hi Grimreaper

- In the Light Cone settings, set 3D Shadows to Enable. That cuts off the light beam through the mirror.

- In the mirror shader, turn down the color. Try Lightness (L) at 2% and Saturation (S) at 50%. That reduces the weird bright spot.

- In the render room, turn on caustics to get the real light bounce effect. Set the filter size to around 50% to smoothen the light dots generated by the render engine. Turn up the intensity if the effect is too weak.

Gerd

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Posted: 23 August 2012 12:54 PM   [ Ignore ]   [ # 3 ]
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I got it to work but I want it to bounce off of 2 mirrors I can’t seem to make that work.I’m going to continue to try.

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Posted: 23 August 2012 01:03 PM   [ Ignore ]   [ # 4 ]
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The light cone doesn’t bounce.

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I find it somewhat liberating not to be encumbered by accuracy.

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Posted: 23 August 2012 01:09 PM   [ Ignore ]   [ # 5 ]
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Oh really well that sucks thanks. If I use a light on a mirror like object will the light bounce off like a normal light (Not a cone just an ordinary light).

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Posted: 23 August 2012 01:34 PM   [ Ignore ]   [ # 6 ]
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This is an on going issue I gave up on. It’s quite clear DAZ can’t fix it. The light cone is an after effect, it wont reflect and even worse lights up items out of it’s light.. As in put a spot above a character in a dark room, now you see the wall behind them lite up even though it is far out of the cone.

Aura is just as bad.

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Posted: 23 August 2012 01:38 PM   [ Ignore ]   [ # 7 ]
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I know that feeling. Also with aura there is the issue of all the weird lines showing up in the render. I also haven’t got enough time to learn maya. Don’t get me wrong carrara is a good 3D program, but I want to play with the beast and tame it.

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Posted: 23 August 2012 01:42 PM   [ Ignore ]   [ # 8 ]
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You could fake the bouncing cone at least for one mirror.

- Set up a second spot behind the mirror.
- Set the Light Cone 3D Shadows to Enable and Invert. This lets the cone start behind the object.

Bouncing light just works by turning on caustics, regardless of the light cone.

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Posted: 23 August 2012 02:04 PM   [ Ignore ]   [ # 9 ]
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Thanks. I prefer to have just one light source it’s kind of like physics. I want to bounce around just one instead of faking it, but if I have to I will.Thanks though I’ll remember it later on when I need to do it.

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Posted: 23 August 2012 02:07 PM   [ Ignore ]   [ # 10 ]
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I was going to suggest a volumetric cloud, as you can use one of those to create a light cone without the limitations of the 3D light cone. Alas, the reflected light doesn’t illuminate the cloud either. It doesn’t matter if I use Caustics, Caustics in conjunction with GI, the Participate in Global Illumination checkbox enabled in the cloud control panel, no matter what I just get one visible cone of light through the clouds. The caustics simulation shows light is bouncing, but I can’t even get the cloud to illuminate from the bounced light even in a diffuse manner. weird.

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Posted: 23 August 2012 02:13 PM   [ Ignore ]   [ # 11 ]
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The_Grimreaper - 23 August 2012 02:04 PM

Thanks. I prefer to have just one light source it’s kind of like physics. I want to bounce around just one instead of faking it, but if I have to I will.Thanks though I’ll remember it later on when I need to do it.


If you were to read the Carrara manual, it says outright that it is a physics simulation, but it isn’t accurate enough to properly simulate a game of pool (their example). The light cone is another example. It would be nice if it obeyed the laws of physics for how light behaves, but it doesn’t. Carrara isn’t a real world physics simulation program. It’s an artistic suite with some basic physics simulations. Bullet adds some enhancements, but it’s not Carrara’s main focus. I suggest you learn to fake some stuff.

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Posted: 23 August 2012 03:02 PM   [ Ignore ]   [ # 12 ]
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The_Grimreaper - 23 August 2012 02:04 PM

Thanks. I prefer to have just one light source it’s kind of like physics. I want to bounce around just one instead of faking it, but if I have to I will.Thanks though I’ll remember it later on when I need to do it.

I feel the same. I’ve been trying to get Carrara to produce physically correct lighting for a while, but haven’t done very well so far. But I come back again and again, feeling that I just have to find the right parameter, setting, hidden feature,...

But in the end, I think evelproducer is right, and we have to surrender to faking. Speaking of that, ManStan prompted me: If Light Cone is a post effect, maybe the cones of the different spots could be rendered out separately and composited together.

There’s another faking feature of Carrara I have refused to look at until now, render passes. These are just three layers, reflection, volume effect of the fist two light cones, and volume effect of the third. Each with visibility and 3D Shadow Invert settings to mask out the rest. I painted out black the parts of the light cones I didn’t want, and blended all three together roughly. It looks promising, and I think, I’ll explore that a bit…

 

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Posted: 23 August 2012 03:57 PM   [ Ignore ]   [ # 13 ]
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GFHEL - 23 August 2012 03:02 PM

But in the end, I think evelproducer is right, and we have to surrender to faking.

Exactly.

And in case you think Carrara sucks in that regard, most CG apps developed over the last 30 years are the same way. They operate differently than what you expect in terms of light “bouncing”. And many/most new 3D’ers encounter the same revelation/disappointment.

To do what you want them to would mean your renders would take vastly longer. So the apps take shortcuts to speed it up, and as a result you lose some abilities. It’s not a bug. Either you can’t simulate light bouncing, or your renders take two weeks. Choose your complaint smile

 

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Posted: 23 August 2012 04:18 PM   [ Ignore ]   [ # 14 ]
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The idea that it’s not realistic also opens up the possibility of artistic license. I know it sounds counter intuitive, but a completely physically correct effect locks you into a rigid scene. The way it stands now, you force perspectives, etc. Of course it requires caution. Get to far out of the box and you lose believability. As an example, think of all the movies out there that take liberties with the laws of physics. Doesn’t matter if it’s light, sound or forces.

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Posted: 23 August 2012 06:20 PM   [ Ignore ]   [ # 15 ]
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I see what you all are saying, and by the way I don’t think carrara sucks because of any lighting issues. There is one thing I like a lot and that is the way carrara does the texturing system. Texturing shouldn’t be to much of a hassle, but doing texture in maya is like working with an entirely new beast and it never seems to turn out right. Also why am I a new member, and when will these forums allow me to search again? What do you think about my latest picture hope you don’t mind http://the—grimreaper.deviantart.com/#/d5c8urw  (To be honest it isn’t my best work).Sorry about the blabbling.

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