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ghostlyfu
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October 9, 2013

360x180 CG Renders

I'm facing a problem when rendering any pair of equirectangular images from inside a 3D modelling package (Maya in my case, but no doubt the same issues apply to many different packages). The attached (side-by-side format) image is an example. I'm hoping the good folk on this forum can help.

I render out my panorama (I use the Lat-Lon Mental Ray lens plug-in) and it looks as you'd expect. Looking at it through the excellent VRPlayer, it works well. I then shift my camera to another position approx 6.5 'virtual' cm to the side of the first position and re-render. Again this panorama works fine on its own.

I was hoping that I could just place these x2 renders side-by-side (as they are in the attached example) to make a 3D version of the scene. Not so. What's happening is that the 'forward' view works fine but the depth gets reversed towards the peripheries of the image (which just looks bad) until the 'back' view is completely inverse (and so look pretty much OK again).

Logically I can see that the reason is that the 'Right camera' becomes the 'Left camera' as it renders the part of the view directly behind itself. However, I haven't got a clue how to fix it and output an equirectangular panorama that works in 3D. Help!

    165 replies

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    MaverickHorn
    Participant
    September 24, 2014
    Hello,

    I rendered a stereo panorama with Unity3d. Maybe you like it:

    https://drive.google.com/file/d/0B2hjEQZblPXqRWpoZUd1S0xzc3M/edit?usp=sharing

    You have to watch it with the Cylinder Projection of the VRPlayer

    The visuell errors can be reduced with a bit more render time. I think in compination with baked Textures from some kind of raytracer it is a possible way to render good looking stereo panorama without spending days for rendering
    leespooner
    New Participant
    October 10, 2014
    "pixelmind" wrote:
    "VanKurt" wrote:
    Vray can do. stereo panorama right out of the render engine.


    Can anyone confirm this?
    I have been playing around with vray and 3ds max, but without any success. I tried creating a camera, setting it to spherical and then adding a stereoscopic camera to the scene. That gave me a split output (L+R), but not really a panorama...


    Yes you can output spherical stereo images directly from vray but not with the default cameras.

    I'm writing a custom camera plugin for 3dsmax and it works quite well.

    Single rendering, no stitching required, works with renderelements and all.

    Here's a test rendering:

    sphericalStereoTest.jpg

    and the same scene in motion:

    http://www.filedropper.com/sphericalstereorendertesthalf

    There's still some warping going on at the nadir and zenith though.


    I presume you are just rendering 2 spherical renders from 2 stationary cameras?
    If so the stereo will be correct where the cameras are facing, to the sides they will be flat, and behind the stereo will be inverted.
    pixelmind
    Participant
    October 10, 2014
    It's one camera which calculates the correct ray vector and position for each pixel as if you would rotate two offsetted cameras around a common axis ( your neck ).

    Take a look at this anaglyph version.
    http://i1.minus.com/ibdmGZBQN1hcMk.jpg

    The stereo offset is correct for the whole image.
    gaoz
    New Participant
    October 10, 2014
    Wow! That is very interesting. Are you planning on sharing your script? :roll:
    twastvedt
    New Participant
    October 11, 2014
    I've been looking for some concrete information on how to calculate the ideal panorama size for viewing on a DK2. Any thoughts? Philipp's example above is 4096x2048 - is that about right? How would I go about calculating the minimum size necessary for one pixel of the image to never occupy more than one pixel of the display screen. (If I'm even thinking about the problem correctly?) Thanks!

    Also, I second gaoz's request to get in on the vray camera scripts! I'd love to be using Vray instead of Mental Ray!
    pixelmind
    Participant
    October 11, 2014
    If I remember correctly the DK2 has a horizontal FOV of around 85 degrees and 1920 pixel in width. So you would propably need 8132x4066 for each eye. To be on the safe side and use nice round numbers: 8192x4096.

    But getting 8Kx8K ( stereo Top/Bottom ) footage to play smoothly could be a challenge :shock:. I allready struggle to view 4Kx4K@30FPS. I don't own a DK2 yet so I'm not sure if watching 4K panoramas in it looks horrible but even for the DK1 it gets blurry if you go below 4K.

    Yes, I would like to share the plugin but at the moment I'm not allowed to do so.
    I started to write it in my spare time but the studio I work for picked it up for a project we're currently working on.
    I've been told I might release the plugin later this year after the project is completed.

    That or Vlado and his team create a native Vray solution before I can share anything :D
    twastvedt
    New Participant
    October 11, 2014
    Ok, we'll wait with anticipation! Philipp, any chance you could share your camera shader?

    About the resolution. is the DK2 horizontal FOV 85 degrees for each eye? I have one, how would I find out? Since the eyes are overlapping, it doesn't seem to me you would need nearly 8k, but maybe I'm wrong. If the eyes are mostly overlapping, then you only have 960 pixels for 85 degrees, right?
    pixelmind
    Participant
    October 11, 2014
    Yeah you're right, sry my bad.
    Seems like it's around 84 degree for 960 pixels ( not taken the distortion and black borders into acount )
    https://developer.oculusvr.com/forums/viewtopic.php?f=26&t=11266
    gaoz
    New Participant
    October 12, 2014
    "pixelmind" wrote:
    If I remember correctly the DK2 has a horizontal FOV of around 85 degrees and 1920 pixel in width. So you would propably need 8132x4066 for each eye. To be on the safe side and use nice round numbers: 8192x4096.

    But getting 8Kx8K ( stereo Top/Bottom ) footage to play smoothly could be a challenge :shock:. I allready struggle to view 4Kx4K@30FPS. I don't own a DK2 yet so I'm not sure if watching 4K panoramas in it looks horrible but even for the DK1 it gets blurry if you go below 4K.

    Yes, I would like to share the plugin but at the moment I'm not allowed to do so.
    I started to write it in my spare time but the studio I work for picked it up for a project we're currently working on.
    I've been told I might release the plugin later this year after the project is completed.

    That or Vlado and his team create a native Vray solution before I can share anything :D


    Thanks for the answer, it is completely understandable! We'll be waiting patiently then ;)
    Sneer
    Participant
    October 27, 2014
    "kimblarsen" wrote:
    If you are using Maya or Max with Mental Ray you can use this stereoscopic shader to render out 360x180 stereo panoramic images:
    http://www.andrewhazelden.com/blog/2012/04/domemaster3d-stereoscopic-shader-for-autodesk-maya/

    "The Domemaster stereo shader is designed to create 2D & 3D fulldome renderings for use in planetariums and other fulldome theaters, and spherical/equirectangular renderings with the latlong_lens shader."

    Cheers,
    Kim Baumann Larsen
    @kimusan


    Really cool, ̶i̶̶s̶̶ ̶̶t̶̶h̶̶e̶̶r̶̶e̶̶ ̶̶a̶̶ ̶̶s̶̶t̶̶e̶̶p̶-̶t̶̶o̶-̶s̶̶t̶̶e̶̶p̶̶ ̶̶g̶̶u̶̶i̶̶d̶̶e̶̶ ̶̶a̶̶v̶̶a̶̶i̶̶l̶̶a̶̶b̶̶l̶̶e̶̶?̶̶ ̶̶i̶'̶v̶̶e̶̶ ̶̶a̶̶d̶̶d̶̶e̶̶d̶̶ ̶̶t̶̶h̶̶e̶̶ ̶̶l̶̶a̶̶t̶̶l̶̶o̶̶n̶̶g̶̶ ̶̶i̶̶n̶̶ ̶̶t̶̶h̶̶e̶̶ ̶̶c̶̶a̶̶m̶̶e̶̶r̶̶a̶̶ ̶̶s̶̶h̶̶a̶̶d̶̶e̶̶r̶̶s̶̶,̶̶ ̶̶b̶̶u̶̶t̶̶ ̶̶w̶̶h̶̶a̶̶t̶̶ ̶̶n̶̶o̶̶w̶̶?̶
    Nevermind, it works with the domemaster stereo shader :)
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