A 360 display

I’ve been approached to make some stuff for a 360 led display a big ring facing outwards rather than in. Now I know about spreading viewports for projectors but that makes seams where they meet, I could up the spread count of viewpors but things slow down then…
I kind of need a slitscan I think
Any ideas of way to do this without lots of spreaded viewports?

hi cat !

i don’t think you need slitscan.
did you already try that patch i posted here?

no seams should be visible, independant from how many viewports are used.

what kind of content should be shown at the end? 2d or 3d?

Currently working (@DigitalSlaves and I ) on a
dome projection setup (5 beamers) and this smart patch is really helpfull.

Thank you again Sebastian :)

yippiee!!! :)
you’re welcome des…

Hi Sebastian!
Content should be 3d I think.
I understand your patch, but this doesnt use separate projectors its one cylinder of LED’s. The input needs to be a ultra wide letterboxed video rather than a single view so I was thinking of just the cameras ( the middle renderer of your patch) without projecting on geometry rather then more cameras and stitching the output of those. I got too much on this week to think on it really, next week I’ll get back to you!

@Des Dont make your self travel sick with that! I’m jealous I got mine almost finshed then didnt have time to get in the dome to test it all out!

hi cat,

okok, i understand. (now…)
the problem somehow was to get the cylinder flat again.

the solution is to use the same projection/undistortion technique like before, but only to have another look onto the cylindrical object.

i also needed a little bit to sort that out:

  • the way how the texture was mapped onto the cylinder worked already with that demo patch. no distortions are visible anymore, even when only 3 or 5 cams look at the 3d scene. the seams between the views disappaer by projecting onto the geometry. so, what worked was the texture mapping - the calculation of the texture coordinates.

  • the geometry (Positions of the vertices) together with the camera decide how an object appaers in the renderer. in our case the cylindrical object. we don’t want to see it as a cylinder, but as a flat shape. the texturing should stay unaffected by that. like if we would want to take the canvas off from the cylinder an put it on a flat wall.

the solution was now

  • to create the cylindrical geometry in the shader,
  • use that cylindrical geometry for projecting the texture (like before),
  • but use flat pos coordintes (like generated by the Grid (EX9) to render the surface of the imaginary cylinder…

hope that helps,

small setup.zip (14.2 kB)

Ahh! Thanks I’ll check that out when I have a minute, I’m glad it wasn’t my thinking that was totally amiss
Your a star!


Yeah! is a really usefull patch.
Thanks a lot.

… a star … britney … paris …

but is he ready to LEAD?!?

cat, i really appreciate comments like that!

;) XD hihi

I’ll come see your show!

Patch is perfect btw, saved me some head scratching there,