PTGui Viewer shows a black spot at the nadir

[Christoforos Vasilakis]

The standalone PTGui Viewer incorrectly shows a black spot at the nadir. However, the Panorama Editor's Detail Viewer renders the same area perfectly without any missing data.

Environment:
- PTGui Version: 13.7
- PTGui Viewer version: v2.10
- Operating System: Windows 11

Attachments:
1) Screen recording from PTGui Viewer
2) Reference 360 image: https://www.swisstransfer.com/d/167a3ca6-0df2-496d-a05d-5590ecc02604

[Christoforos Vasilakis]

Extra Attachments: 

1) Screen recording from Detail Viewer (correct rendering)

2) Screenshot from the Panorama editor

[Erik Krause]

Am 15.04.2026 um 18:35 schrieb Christoforos Vasilakis:

> 2) Reference 360 image:
> https://www.swisstransfer.com/d/167a3ca6-0df2-496d-a05d-5590ecc02604

The image is 21636 x 6958 pixels and therefore not a full
equirectangular. The zenith is missing, while the nadir is there. The
PTGui Viewer doesn't know this, and displays an equal sized black circle
in both zenith and nadir. To fix this, you must export as a full
equirectangular 21636 x 10818 pixel image.

--
Erik Krause
http://www.erik-krause.de

[Christoforos Vasilakis]

Thank you very much for explaining the cause!

It would be absolutely optimal if the standalone PTGui Viewer could auto-detect when an image is a partial equirectangular (where the nadir is present but the zenith is missing) based on the file's metadata or dimensions, rather than assuming an equal distribution of missing data.

The main reason I avoid exporting as a full 21636 x 10818 equirectangular with black zenith pixels is that doing so prevents the top bar from forming a perfect circle, something that my current cropped version achieves perfectly.

Thanks again for the excellent support and for considering this improvement!

Best regards,
Christoforos

[Erik Krause]

Am 15.04.26 um 22:52 schrieb Christoforos Vasilakis:

> The main reason I avoid exporting as a full 21636 x 10818 equirectangular
> with black zenith pixels is that doing so prevents the top bar from forming
> a perfect circle, something that my current cropped version achieves
> perfectly.

What viewer would show that as a spherical panorama with a closed nadir,
but a circular hole in the zenith? In most viewers I know of you need to
specify an upper tilt limit, in which case the actual upper edge
wouldn't be seen anyway.

PTGui pro has an option Fill Holes, which fills in an even color with
adaption to the edges of the hole.

But the very best option is of course to shoot the sky. You can do that
with your drone after landing, if you turn it upside down, or with a
different camera from the ground. Then simply add those images to your
project.

--
Erik Krause

[Christoforos Vasilakis]

>  What viewer would show that as a spherical panorama with a closed nadir,
> but a circular hole in the zenith?

Thanks a lot for the suggestions!

In android it is quite common for apps to handle spherical panorama images with a closed nadir, but a circular hole in the zenith correctly.

For example the open source Aves ( https://github.com/deckerst/aves ) gallery can open the shared image in panorama (360) mode. You can try it by downloading the app from the GitHub and the shared image from my first message ( https://www.swisstransfer.com/d/167a3ca6-0df2-496d-a05d-5590ecc02604 ). Also google photos opens the same image correctly (screen recording attached).

In windows i have not found any viewer that handles this correctly. The PTGui Viewer is the best i have tried so far in windows.

Kind regards,

Christoforos

[Erik Krause]

Am 16.04.2026 um 22:02 schrieb Christoforos Vasilakis:

> For example the open source Aves (https://github.com/deckerst/aves )

> gallery can open the shared image in panorama (360) mode. You can try it by
> downloading the app from the GitHub and the shared image from my first
> message

> (https://www.swisstransfer.com/d/167a3ca6-0df2-496d-a05d-5590ecc02604 ).

> Also google photos opens the same image correctly (screen recording
> attached).

You are right, but that's interesting: The image contains the metadata
parameter and value Xmp:CroppedAreaTopPixels 3860, which means, PTGui
must have written this value. It's in the XMP-GPano section, which is a
google invention. There is also the full equirect size. So any viewer
could and the PTGui Viewer should read that and display it correctly.

Joost?

[PTGui Support]

You're right. PTGui writes the GPano metadata, but the PTGui Viewer
doesn't read this currently. I'll add it to the wish list.

Kind regards,

Joost Nieuwenhuijse
www.ptgui.com