Why do most laser format (like ILDA) include a Z (depth) value ?

[MarcDorpe]

Hello,

I was taking a look at this page (which describe the ILDA file format) and was wondering why is there a support for 3D points ?

AFAIK no laser today can display/use such data (they simply move the laser mirros left/right and up/down using 2D X/Y coordinates).

In this case the Z value would mean : low value = near laser, high value = far away, near audience)

Is this information used in any way today ? (because lot of file seems to use 3D format, and Z is not set to zero...)
Or is a bet for the future ? (so it is not used now, but could be one day, if technology evolve...)

[swamidog]

Hello,

I was taking a look at this page (which describe the ILDA file format) and was wondering why is there a support for 3D points ?

AFAIK no laser today can display/use such data (they simply move the laser mirros left/right and up/down using 2D X/Y coordinates).

In this case the Z value would mean : low value = near laser, high value = far away, near audience)

Is this information used in any way today ? (because lot of file seems to use 3D format, and Z is not set to zero...)
Or is a bet for the future ? (so it is not used now, but could be one day, if technology evolve...)

sure, the mirrors only handle x/y, but internally z-data can be used for depth shading, clipping, and object rotation on the software side.

[VDX]

... or you have an optional autofocus to project on a curved screen ... or you use it for an engraver with Z-axis ... or otherwise

Viktor

[masterpj]

Its there with the idea to have some realtime live manipulation of frames.. However it's very inefficient and some of those XYZ graphics are really hard on scanners I don't recommend them :b

[mixedgas]

Stereoscopic 3D is possible with the correct optical systems and with proper 3D glasses. You do not see it much anymore, and very few people left in the industry still know how to do it. It requires some serious hardware skills to do, unless you use two scanheads or anaglyph stereo. You also need a polarization preserving screen material. The proper polarization maintaining screens are becoming much more common because of modern video projectors.

You also need non-dichroic, metallic mirrors on the galvos if using polarization techniques. Modern Dichroic mirrors often rotate polarization at different rates with respect to wavelength.


You can do, as a few examples, Polarization flipping using EO cells on a single scan head, Anaglyph, two scan heads and polarization, Chromadepth Goggles, Lenticular back projection ,Field Sequential, LCD shutter glasses etc. Most of the video and film 3D techniques work if you have a polarized laser beam to begin with.



Steve

[masterpj]

I wouldn't say it is inefficient but it's true that it can be tough on scanners if the software doesn't have good dynamic optimization.

Usually the files are left untouched and there are a lot of parts where the beam passes further into the Z axis but not so much visually moves from the front. However the points within the scene remain. That's why it I named it inefficient.

I know about the Stereoscopic systems using 2 RGB laser sources of different polorized light *horizontal or vertical. However Circular polorization is better but no idea how you'd change a laser source into that.
Systems I know of are Trimagic and a mentioned Ferro-electric liquid crystal system.