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Creating a live camera loop: Render target -> img plane?

Posted: Thu Aug 18, 2016 2:23 pm
by linvanchene
Update / edit:
added some further information how a live camera loop effect could be used in a render engine to create more stylised images without much postproduction efforts.


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live camera loop:
The live image which is captured by a camera is at the same time visible on a display which is also captured by the camera.

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Have you ever watched a sport game that showed a player strike a pose while in the background the same image was shown on the big stadium screen the very moment it was captured by the live camera?
You may be able to observe the same effect during a live music performance.


To illustrate a quick test with a real life monitor and a photo camera.
The action figure is out of focus because a macro lens was not used...
vlcsnap-2016-08-18-15h35m51s849.png
vlcsnap-2016-08-18-15h35m38s742.png
vlcsnap-2016-08-18-15h36m11s508.png
vlcsnap-2016-08-18-15h36m33s561.png
The images are screenshots of video footage.
Depending on the camera when you are trying to photograph a monitor at the split second the picture is taken the feed to the monitor may be interrupted and the screen goes black...

loop black screen result with photo camera.jpg
-> Creating camera loops with a computer graphic render engine would add some artistic options that are not that easy to recreate in real life with photography and a monitor.

- you have more control over object, monitor and camera placement.
- there is huge potential to use live camera loops in animated sequences to create unique effects
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How could a camera loop be integrated into OctaneRender?

Test scene:
- human figure
- vertical image plane (or a 3d monitor object with a flat image output surface)

-> You plug the render target as source into a special type of input node that is connected to the geometry node of the monitor object in the scene.
render target input node.jpg

A way must be found to update the monitor image plane repeatedly with the live source of the already calculated samples.

Example of a manual approach:
- First calculate 100 samples on the main image.
- add the resulting image after those 100 samples into the image plane.
At this moment the light situation in the scene changes because the plane that is now showing the looped source now also has different colors and therefore the reflecting rays etc are affected.
- calculate another 100 samples.
- Repeat until the whole image including the looped surface looks good.


-> To see instant results the render engine could automate this process by automatically updating the image node after every sample.
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Is a camera loops functionality that instantly shows the results in the real time preview render something that could to be added to OctaneRender?

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