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jeric_synergy
08-23-2016, 07:28 PM
What does it take to get a LW light to bounce its light off a mirror onto a second object? :stumped:

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Ztreem
08-24-2016, 03:31 AM
Enable radiosity and directional rays and crank up the reflection value on your mirror.
To get a more visible effect you may need to go way over 100% reflection. Best way to get control over reflected light and get nice reflections in the visible mirror is to have two mirrors. One mirror is the one you see in render with a reflection not higher than 100% then you have a clone mirror that is unseen by camera and unseen by rays and scale it up so it just a little bigger then the actual mirror and have a reflection value of for example 500%.

kopperdrake
08-24-2016, 06:37 AM
Nice tip - thanks!

Spinland
08-24-2016, 06:47 AM
Wow, outstanding tip, thanks! I would have just cheated and added a second light source to simulate the bounce. ;D

Danner
08-24-2016, 07:27 AM
the bounce is necesary and it usually is good enough, but the effect is not the same as in real life, the effect is coser to real life if you enable caustics. You can actually get really close to reality but it takes ages to render if you up the caustics settings.

Danner
08-24-2016, 08:02 AM
like this

Ztreem
08-24-2016, 08:31 AM
yes, for a more accurate result use caustics or luminous polys instead of lights.

I almost never use LW lights anymore, I mostly use luminous polys or HDRI's to light my scenes.

Prince Charming
08-24-2016, 11:55 AM
What does it take to get a LW light to bounce its light off a mirror onto a second object? :stumped:

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I would use ray intersect, nodal motion, and another light. There is a sample scene in the content that will help you. It is about refracting light through a gem. You would have to modify it, but it has all the nodes you need to do this.

jeric_synergy
08-24-2016, 07:55 PM
Wow, outstanding tip, thanks! I would have just cheated and added a second light source to simulate the bounce. ;D
This is just a test to get the settings right: the real thing will involve dozens of moving mirrors. Thought I should check the path first.

For instance, I've found (via reading posts) that volumetric refections are not-going to happen. Fortunately, I don't happen to need them.

madno
08-25-2016, 01:26 AM
Hi,

just some fun with luminous geometry as lightsource.
The LW spotlight is off in scene editor.
Rendertime was 58 sec.

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jeric_synergy
08-25-2016, 08:59 AM
Very nice, but which bit is luminous?

madno
08-26-2016, 01:01 AM
see screenshot.

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jeric_synergy
08-27-2016, 03:09 PM
So I re-did my test scene to simplify it, and got good results.

Surprisingly, pour moi, is that I did NOT have to crank up Reflection to some weird >100% number: in fact, reflecting a 62/255/111 light at 100% (both light and channel) resulted in highly blown out spots in the render, blowing out to white! So that's good.

This simple scene might help somebody who was as clueless as I to experiment with reflected light-- you can scootch the mirror/black divisions around to see how they work out-- dang, I shoulda done it with Instancing and then you'ld only have to move ONE Edge to get the effect.... ah well. It's free. ;)

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