I have the need for a custom camera, specifically an omni directional
stereoscopic panorama (cylindrical, not equirectangular). I've done this in the
long distant past by modifying the source and building my own version.

I thought I would try the mesh_camera but it seems not as useful as I imagined.
I can readily create the meshes and am getting the right results but ...

1. Loading the mesh takes a very long time for high resolution images. The LED
cylinder I'm creating for is 12816x2048 pixels, even for 1/4 resolution tests
the mesh loading takes longer than the rendering and it's probably 16x longer
for the full resolution.

2. Is there there still no efficient/clean way to do antialising.

Am I missing something?

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"Paul Bourke" <pau### [at] gmailcom> wrote:
> I have the need for a custom camera, specifically an omni directional
> stereoscopic panorama (cylindrical, not equirectangular). I've done this in the
> long distant past by modifying the source and building my own version.
>
> I thought I would try the mesh_camera but it seems not as useful as I imagined.
> I can readily create the meshes and am getting the right results but ...
>
> 1. Loading the mesh takes a very long time for high resolution images. The LED
> cylinder I'm creating for is 12816x2048 pixels, even for 1/4 resolution tests
> the mesh loading takes longer than the rendering and it's probably 16x longer
> for the full resolution.
>
> 2. Is there there still no efficient/clean way to do antialising.
>
> Am I missing something?

Hi! Wouldn't using stochastic sampling ("AM3") with zero value for aa but a tiny
camera depth of field "aperture" so that you can keep its sample count minimal
between 3 and 5, the whole thing focused at the distance of your cylinder's
surface do the trick for you ? (I often ended uo using no aa and using only
aperture instead in the cases where I wanted some really photographic look
anyway. and it ended being a better trade off.

Otherwise, Le Forgeron's branch (HGPOVRAY38) has many additional camera types,
(among which a stereo one) does none suit your use?

Post a reply to this message

On 06/10/2025 10:01, Paul Bourke wrote:
> I have the need for a custom camera, specifically an omni directional
> stereoscopic panorama (cylindrical, not equirectangular). ...
I remember your 'Market' project:
https://povlab.yesbird.online/pb/

For rendering this animation I used HgPovray38:
https://github.com/LeForgeron/povray
with Omni Directional Stereo camera:
https://wiki.povray.org/content/User:Le_Forgeron/cameras
and then, applied video to cylinders with Three.js.

I guess the projection is fine and without noticeable distortions.
After exploring mesh cameras I switched to HgPovray, as a more reliable
solution.
-- 
YB

Post a reply to this message

On 10/6/2025 12:01 AM, Paul Bourke wrote:
> I have the need for a custom camera, specifically an omni directional
> stereoscopic panorama (cylindrical, not equirectangular). I've done this in the
> long distant past by modifying the source and building my own version.
> 
> I thought I would try the mesh_camera but it seems not as useful as I imagined.
> I can readily create the meshes and am getting the right results but ...
> 
> 1. Loading the mesh takes a very long time for high resolution images. The LED
> cylinder I'm creating for is 12816x2048 pixels, even for 1/4 resolution tests
> the mesh loading takes longer than the rendering and it's probably 16x longer
> for the full resolution.
> 
> 2. Is there there still no efficient/clean way to do antialising.
> 
> Am I missing something?
> 
> 
In my Mesh Camera experiments I stole some code from Jaime Vives 
Piqueres on how to save the meshes to files once I had generated them so 
subsequent renders went faster.

The only way I've found to anti-alias is to use multiple copies of the 
mesh moved along the view plane. This also allowed for focal blur and 
motion blur. Since meshes are quick to copy this doesn't add a lot of 
overload.

I've started to experiment with the user-defined camera but I'm not 
getting results yet. The user-defined camera supposedly supports 
anti-aliasing.

Josh

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Attachments:
Download 'meshcam07c.png' (211 KB)

Preview of image 'meshcam07c.png'

> Hi! Wouldn't using stochastic sampling ("AM3") with zero value for aa but a tiny
> camera depth of field "aperture" so that you can keep its sample count minimal
> between 3 and 5, the whole thing focused at the distance of your cylinder's
> surface do the trick for you ? (I often ended uo using no aa and using only
> aperture instead in the cases where I wanted some really photographic look
> anyway. and it ended being a better trade off.

Antialiasing is not about depth of field.
The distance to the cylinder is related to where zero parallax in the ODSP.

> Otherwise, Le Forgeron's branch (HGPOVRAY38) has many additional camera types,
> (among which a stereo one) does none suit your use?

Yes, the "Omni Directional Stereo camera" in HGPOVRAY38 is what I'm looking for,
but while building version 3.7 works out of the box on MacOS, I haven't been
able to build HGPOVRAY38 yet. Anyone done this? Preferably just the command line
version, no gui.

Post a reply to this message

yesbird wrote:
> On 06/10/2025 10:01, Paul Bourke wrote:
> > I have the need for a custom camera, specifically an omni directional
> > stereoscopic panorama (cylindrical, not equirectangular). ...
> I remember your 'Market' project:
> https://povlab.yesbird.online/pb/
>
> For rendering this animation I used HgPovray38:
> https://github.com/LeForgeron/povray
> with Omni Directional Stereo camera:
> https://wiki.povray.org/content/User:Le_Forgeron/cameras
> and then, applied video to cylinders with Three.js.
>
> I guess the projection is fine and without noticeable distortions.
> After exploring mesh cameras I switched to HgPovray, as a more reliable
> solution.

Yes, the "Omni Directional Stereo camera" in HGPOVRAY38 is what I'm looking for,
but while building version 3.7 works out of the box on MacOS, I haven't been
able to build HGPOVRAY38 yet. Anyone done this? Preferably just the command line
version, no gui.

Post a reply to this message

> In my Mesh Camera experiments I stole some code from Jaime Vives
> Piqueres on how to save the meshes to files once I had generated them so
> subsequent renders went faster.

I saw your work and examples, it was useful when I started exploring the
mesh_camera, so thanks.

I'm creating them as an inc file also, except I'm creating them from C/C++.

But the issue remains, for high resolution images reading the mesh data is slow.
But without (efficient) antialiasing I've decided to drop this as an option.

Post a reply to this message

"Paul Bourke" <pau### [at] gmailcom> wrote:

> "Omni Directional Stereo camera"

Have you looked at the "User defined projection" in POV-Ray 3.8?

https://wiki.povray.org/content/Reference:Camera#User_defined_projection

An ODS camera has been built with it:

https://www.clodo.it/blog/omnidirectional-stereo-ods-with-pov-ray/

ingo

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On 09/10/2025 06:30, Paul Bourke wrote:
> Yes, the "Omni Directional Stereo camera" in HGPOVRAY38 is what I'm looking for,
> but while building version 3.7 works out of the box on MacOS, I haven't been
> able to build HGPOVRAY38 yet. Anyone done this? Preferably just the command line
> version, no gui.

I've built it for Windows and Ubuntu 24.04, if you have some issues
building for MacOS, please send details and I will try to help,
although, unfortunately, I have no MacOS platform.
--
YB

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> Have you looked at the "User defined projection" in POV-Ray 3.8?
> https://wiki.povray.org/content/Reference:Camera#User_defined_projection
> An ODS camera has been built with it:
> https://www.clodo.it/blog/omnidirectional-stereo-ods-with-pov-ray/

Ahhhh, that would be PEFECT. Easy to modify that example to create cylindrical
rather than equirectangular ODSP.

But now back to building 3.8 on MacOS, preferably without the GUI. Anyone with
more skills than I have done this? I didn't succeed with HgPovray38 but perhaps
the base 3.8 version?

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