Maniphest T93059

3D Stereoscopic image render give a BLACK BAR.
Closed, Archived
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Assigned To
None
Authored By
bouich jules (zuraxe)
Nov 13 2021, 3:14 PM
Tags
  • BF Blender
Subscribers
Alaska (Alaska)
bouich jules (zuraxe)
Evan Wilson (EAW)

Description

System Information
Operating system: Windows 10
Graphics card: RTX 3080

Blender Version
Broken: Blender 3.0.0 Beta
Worked: 2.93

Short description of error

Rendering 3D stereoscopic make a BLACK BAR appear in the image, if camera is close to an object.

blackbar.blend924 KBDownload

Exact steps for others to reproduce the error
the .blend file in attachment contain a perfect exemple. you can render any image in 3D top/bottom Stereoscopic ( spherical stereo) if the camera is close to an object you will have an automatic black bar.

blackbar.blend924 KBDownload
,

Event Timeline

bouich jules (zuraxe) created this task.Nov 13 2021, 3:14 PM
bouich jules (zuraxe) added a subscriber: Thomas Dinges (dingto).Nov 14 2021, 7:59 AM

in the blender file you just click on render and the black bar will appear.

Alaska (Alaska) added a subscriber: Alaska (Alaska).Nov 14 2021, 8:47 AM

I'm not 100% certain on this, but I believe everything is working as expected and this is just an issue with your scene.

Your camera is located too close to the object and as such when it renders the left and right perspective inside the object. And since light can't reach the inside of the object, it appears black.

The reason why the camera is going inside the object when you do your render, but not in the viewport, appears to be because of the setting highlighted in the image below with the camera object selected. If you disable this setting, the issue goes away, but the stereoscopy may look weird.

Thomas Dinges (dingto) removed a subscriber: Thomas Dinges (dingto).Nov 14 2021, 10:03 AM
bouich jules (zuraxe) added a comment.EditedNov 14 2021, 11:02 AM

It's not only my scene ( which is a super simple scene for explanation), but every scene, when the camera is close to an object it's a black bar.

and i cant disable the spherical stereo, without it the scene looks weird and ridiculous.

so this issue of black bar if camera is close to an object is normal ? , ( i made sure that the camera is not INSIDE an object but OUTSIDE) but still black bar when a bit close.

Alaska (Alaska) added a comment.EditedNov 14 2021, 11:46 AM

I believe the Spherical Stereo option is what's causing the issue as the left and right perspectives are moved a little bit away from the camera and inside the object. So although the camera isn't inside the object, the left and right perspectives are. I believe the different perspectives moving away from the camera is intentional and as such the camera moving inside the object and rendering with the black bar is technically not a bug. However I'm not 100% sure if the perspectives are supposed to move in the directions observed. So this might still be a bug in a sense.

Basically, the black bar is not a bug, the camera is rendering the inside of an object which is black due to a lack of light.
The question is if the perspective offset with the Spherical Stereo option is incorrect. If it is, then that's the bug. However, I do not believe Spherical Stereo is working incorrectly, but this will need to be confirmed by someone else.

In T93059#1253444, @bouich jules (zuraxe) wrote:

and i cant disable the spherical stereo, without it the scene looks weird and ridiculous.

Yes, thinking about what the feature does now (based on my knowledge of it), disabling this feature will make the scene look weird.

Evan Wilson (EAW) closed this task as Archived.Nov 15 2021, 5:26 PM
Evan Wilson (EAW) added a subscriber: Evan Wilson (EAW).

Below the Normal pass showing that the "black bars" are the inside of the cone.

You have your far clip plane set to 10m, but your convergence plane distance set to 100m.
Your near clip plane is 0.001m and the interocular distance is 0.1m
Lowering the interocular distance to 0.01m eliminates the camera going inside of the cone.


Reseting the interocular distance and convergence plane to the defaults by pressing backspace while hovering over them reveals that the respective defaults are 0.00065m and 0.0195m.

The low values are due to your scene scale being set to 0.01.


This makes the unscaled scene interocular distance equal to10m! This causes extreme hyperstereopsis. Hyperstereopsis increases ocular convergence and causes near objects to appear closer and with exaggerated depth and slant.

The manual states:

Spherical Stereo

Render every pixel rotating the camera around the middle of the interocular distance.

Here I have added a sphere with r=0.05m, which shows that this rotation causes the cameras to go into the cone, which is only 0.030585m from the camera.


Here is the interocular distance set to 0.01m, and a sphere with r=0.005m

If you don't want to clip into any objects, the interocular distance can be set to <=2x the distance to the nearest object.
For this setup, that is 0.06117m

As the effect of seeing inside the cone is caused by extreme values, and not a bug in Blender, I will close this report.