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 Post subject: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 7:35 pm  (#1) 
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I was attempting to simulate Light Probe images, which can be thought of as taking a picture of the reflection in a mirrored ball (like a silver Christmas tree ball). Not all images seem to work well as Light Probe Images for emaps. Some need lots of smoothing, at some point during the process, to produce good results.

I've been playing with a script to do this, which basically does what I manually outline below. While this method produces a cool effect, maybe someone can offer suggestions on how to improve the technique for simulating Light Probe images.

Menu: Filters/Distort/Light Probe Simulation

Image

Attachment:
File comment: Light Probe Simulation Beta V0.90
light-probe-simulation.scm [3.26 KiB]
Downloaded 209 times

Note: You can also get interesting results by running the script twice: once at 10% Circular Warp Depth, then on that result, run again at 100% Warp Depth.


Wallace wrote:
Hey Tux, how exactly do you make these e-maps using an image?
You can do it manually using Filters/Polar Coordinates.

Image

Step #1 - Run Polar Coordinate using these settings.
Image

Step #2
Image/Transform/Flip Vertically

Step #3 - Run Polar Coordinate using these settings.
Image

You might also want to lake a look at this thread and this thread.

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 Post subject: Re: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 10:08 pm  (#2) 
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Looks pretty good/cool Tux. :bigthup
I'm not sure what I might add to make the outcome look any better then it does now. :jumpclap

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 Post subject: Re: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 10:56 pm  (#3) 
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Darla's Amazing circle script-fu can be coaxed to create these light probe results too. I had modded it to leave the transparentcy intact so your's already does this Tux which is cool. :)

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 Post subject: Re: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 11:09 pm  (#4) 
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The problem with this method is that it doesn't simulate light probe made with mirrored ball reflection.
Pinching in the middle should not occur, it's like a Universe inside out. Added grid for demonstration

ImageImage

Pixels in light probes don't really converge, gives incorrect reflections.
Maybe it's not important for text reflections using Bevel Reflect plugins
but it wouldn't work as a general purpose light probe creation.


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 Post subject: Re: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 11:30 pm  (#5) 
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Yes. I'm aware this is not a perfect simulation, but more of an approximation. I was actually hoping for constructive suggestions on how it might be improved or alternate methods of achieving the effect, perhaps like multiple levels of lens distortions or something along those lines.

Thanks!

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 Post subject: Re: Light Probe Simulation?
PostPosted: Wed Jul 16, 2014 11:31 pm  (#6) 
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GnuTux runs very smoothly and creates lovely Images :bigthup
Image

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 12:08 am  (#7) 
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Doing a little testing with a photo I took of NYNY in Vegas.

Image

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 12:24 am  (#8) 
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I hear you Tux. I've searched for the solution myself not so long ago.
None is good enough. Approximations.
BTW, your script is similar to what GMIC>Deformations>Circle_transform does.

Surprisingly, not so many software programs can convert panoramic HDRi (or just jpeg) images into a [physically correct] light probe.
HDR Shop is the only program that I know of. I was told that Genetica can also do the trick. They are all commercial, of course.
No wonder 3D artists still stick to DSLR cameras and gazing balls. :hehe


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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 1:53 am  (#9) 
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Could some one point me to how to use these light probe images to create text effect?
I want to use the below image I tried to create to see how it looks with text effect
Image
it isn't perfect but it's worth a try.

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 3:03 am  (#10) 
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trandoductin wrote:
Could some one point me to how to use these light probe images to create text effect?
I want to use the below image I tried to create to see how it looks with text effect
it isn't perfect but it's worth a try.

Image

If you don't have Bevel Reflect Logo look here... http://gimpscripts.com/?s=bevel+reflect

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 6:30 am  (#11) 
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trandoductin wrote:
Could some one point me to how to use these light probe images to create text effect?
I want to use the below image I tried to create to see how it looks with text effect
[ Image ]
it isn't perfect but it's worth a try.


viewtopic.php?f=23&t=9817&hilit=+bevel&start=0
viewtopic.php?f=9&t=9650&hilit=+bevel&start=0
viewtopic.php?f=11&t=9242&start=100
:)

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 Post subject: tmp
PostPosted: Thu Jul 17, 2014 12:43 pm  (#12) 
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Here my three last ones. :)


Attachments:
LightProbe-flower.png
LightProbe-flower.png [ 1.2 MiB | Viewed 1380 times ]
LightProbe-colours.png
LightProbe-colours.png [ 483.17 KiB | Viewed 1380 times ]
LightProbe-vegetables.png
LightProbe-vegetables.png [ 783.9 KiB | Viewed 1380 times ]

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 Post subject: tmp
PostPosted: Thu Jul 17, 2014 2:15 pm  (#13) 
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Just thought I would share this since it's sort of related to this thread. I used the Distort Twist preset (default set choosing box 5) and it comes close to mimicking a spherical light map (did did resize to square before running the filter). I think this preset can be coaxed to create these. :)


Attachments:
L1000037_twst.JPG
L1000037_twst.JPG [ 1002.09 KiB | Viewed 1377 times ]

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 Post subject: Re: Environment Map Sharing Thread (Spherical)
PostPosted: Thu Jul 17, 2014 2:30 pm  (#14) 
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lylejk wrote:
Just thought I would share this since it's sort of related to this thread. I used the Distort Twist preset (default set choosing box 5) and it comes close to mimicking a spherical light map (did did resize to square before running the filter).

What Plug-in are you referring to, Lyle? I'm not sure where "Distort Twist" is located.

I like the result! :bigthup

Thanks!

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 Post subject: Re: Environment Map Sharing Thread (Spherical)
PostPosted: Thu Jul 17, 2014 2:38 pm  (#15) 
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Is it in MathMap. Zoom twist

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 Post subject: Re: Environment Map Sharing Thread (Spherical)
PostPosted: Thu Jul 17, 2014 2:47 pm  (#16) 
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molly wrote:
Is it in MathMap. Zoom twist

Thanks Molly. That explains it. :hehe

I probably wouldn't want to force a user to have to install mathmap to use this script. It can be difficult to get mathmap installed, depending on your OS/Version.

I could add it as an option though. Perhaps I just need to take a look at the mathmap source code to see what might be required to convert the twist algorithm to a script.

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 2:53 pm  (#17) 
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Not a Mathmap plugin; it's a cool plugin that I used for my butterfly wings a while back. lol

:)

http://registry.gimp.org/node/13221

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 2:58 pm  (#18) 
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Ah, Molly must have been referring to another "twist" option.

I've grabbed the source code for Twist 2.0. Hopefully, it will compile OK under Linux.

Thank for the suggestion, Lyle. :cool

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 3:03 pm  (#19) 
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:oops: :oops:

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 Post subject: Re: Light Probe Simulation?
PostPosted: Thu Jul 17, 2014 3:15 pm  (#20) 
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Below took forever for my aging PC to render, but talk about a cool result. Used the twist output as the light map. :)

Attachment:
L1000040twist.jpg
L1000040twist.jpg [ 951.27 KiB | Viewed 1350 times ]


Output:


Attachments:
sample.png
sample.png [ 440.94 KiB | Viewed 1350 times ]

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