Animations for 3d holographic displays

[Thomas Leong]

It is based on the maths principle “Angle of Inflection equals Reflection”.

Essentially, the video animations are created over a layer of an outline of the bottle. When done, this bottle layer is not rendered. When the rendered animation is played back in the manner shown (reflected, in this case, at a 45-degree angle since the monitor is horizontally flat at the top of the ‘box’ housing), the eye sees the animation exactly over and ‘around’ a real physical bottle placed behind the one-sided silver-surfaced mirror. The position of the real bottle is equidistant to the monitor above – angle of inflection equals reflection.

[Melvin Coutinho]

Thanks for your prompt reply, so basically I have to take exact mesururements / photograph the physical object, create outline of object on a layer, create animations and play the movie on the screen.
Correct me if wrong

Thanks

[Thomas Leong]

Basically that procedure you outlined is correct.

Another method is trial-and-error if you have the mirror contraption built first. Then you test your rendered output against the real object placed behind the mirror. You can then re-scale your animations and re-render to fit the real object. For sure, accurate measurement/representation in your creation software is the more accurate way to go.

Re the mirror, you could use a piece of perspex/plastic for tests. However, be warned that plastic warps when positioned at an angle. Even glass warps for big pieces unless thick enough. If the ‘mirror’ is not silver-surfaced on one side, the reflected image is not so clear. You could try tinted glass, but the darker the tint, the darker the object behind the glass, so a stronger light on the object may be used to compensate. Additionally, the thicker the mirror, the greater the ghosting (owing to reflections from both sides of the glass/plastic), unless silver-surfaced on the reflective side only (eg. teleprompter glass). Without the silver-surfaced coating, the thinner the glass, the less visible the ghosting, but the greater the chances of warping, especially with large pieces. It is a compromise.

[Melvin Coutinho]

I am using tinted glass with a bright led & full hd display in my construction ,this setup is giving me a sharp output. Though I would give teleprompter glass a shot.
The mapping part is really getting me intrigued & I don’t seem to get a definitive solution .
I would definitely try the trial & error method described by you.
In the meantime would really appreciate if you come across some other method which gives accurate results.
Thanks a lot for your precious time.

[Thomas Leong]

I’d save money re the teleprompter glass for the moment…till you have solved your other problems. In fact if the reflected images are sharp, clear and bright enough owing to the LED monitor, you may not need teleprompter type glass. Silver-surfaced mirrors are more essential for relatively static images like text, etc. Otherwise, you may get away with cheap plate glass. However, if you do need silver-surfaced mirrors, sometimes called beamsplitters, here is a possible sources for that –
EdmundOptics for beamsplitters – https://www.edmundoptics.com/optics/beamsplitters/

…or try making your own – https://forums.creativecow.net/readpost/158/857831 from the youtube videos I included in the post.

The entire technique is basically called ‘Pepper’s Ghost’ invented by Dr. Pepper back in the 1800’s.
Google is your friend.

Edit: Forgot to add…when lighting the real object, keep the section where your animations occupy the same space or XYZ position as the real object, dark. Look at the cola bottle in your posted example. The liquid is dark and so is the front of the real bottle. This ensures that the reflected video is more clearly visible and there is minimal ‘see-through’/ghosting/superimposition that would immediately reveal that it is a mere reflection of images.