Inconsistent visibility in the viewport for large scenes #87834

New Issue

Sebastien Larocque · 2021-04-26T16:09:56+02:00

2021-04-26 16:09:56 +02:00

System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30

Blender Version
Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: 02948a2cab
Worked: Never.

Short description of error
Inconsistent visibility in the viewport for large scenes.

Exact steps for others to reproduce the error

Open the test project attached.
Notice the way that the objects are displayed by moving the view around with the mouse.

The result is that the objects are drawn with artifacts. They appear to me like the front of the spheres is only partially drawn and we can see the back of the spheres. Note that the rendering of the grid and axis lines are also affected (not rendered in the far distance).

I reported this issue because the objects are not rendered as expected in the viewport. I believe there are two points of view to this issue: from the users and from the developers.

From a users’ perspective it is glitchy. We don’t expect that. Clearly, a user will tell you that there is a problem displaying the information in the viewport.
From the developers’ perspective (I’m a software developer too), I expected more something like normal behavior because the large scale and lack of precision with the floating point numbers. I’m not sure exactly about the cause, but it seems to have something to do with the “Clip Start” and “Clip End” parameters because changing them either creates or fixes the problem depending on the scale.

Solution:
Although this might be normal because of the way it is programed, I see a relatively easy solution. The first solution for the user is to change the “Clip Start” value to a higher value when working with large scenes where the “Clip End” value is already set to a high value. Just changing the “Clip Start” value from 0.01m to 0.5m fixed the problem in the test project.

As a solution, from a programming point of view, rendering the large and far objects from different lists with a higher “Clip Start” would be a solution. If rendering all objects works correctly by changing the “Clip Start” parameter manually, it should work when rendering different groups of objects. This is what I would call an adaptive solution. It adjusts the clipping parameters based on the objects size and distance to ensure a better rendering. The clipping parameters are set for all objects, but if adjust them for each object or (group of objects), you are going to get the best result for each object. I have not seen the code yet, but I’m trying to propose a realistic solution from my user and developer's point of view. Maybe it is not possible because of the z-buffer settings. I presume there must be a solution in terms of programing.

LargeSceneInconsistentVisibility.blend

Clip Start 0.01m
{F10039304 size=full}

Clip Start 0.5m
{F10039307 size=full}

**System Information** Operating system: Windows-10-10.0.19041-SP0 64 Bits Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 457.30 **Blender Version** Broken: version: 2.92.0, branch: master, commit date: 2021-02-24 16:25, hash: `02948a2cab` Worked: Never. **Short description of error** Inconsistent visibility in the viewport for large scenes. **Exact steps for others to reproduce the error** * Open the test project attached. * Notice the way that the objects are displayed by moving the view around with the mouse. The result is that the objects are drawn with artifacts. They appear to me like the front of the spheres is only partially drawn and we can see the back of the spheres. Note that the rendering of the grid and axis lines are also affected (not rendered in the far distance). I reported this issue because the objects are not rendered as expected in the viewport. I believe there are two points of view to this issue: from the users and from the developers. * From a users’ perspective it is glitchy. We don’t expect that. Clearly, a user will tell you that there is a problem displaying the information in the viewport. * From the developers’ perspective (I’m a software developer too), I expected more something like normal behavior because the large scale and lack of precision with the floating point numbers. I’m not sure exactly about the cause, but it seems to have something to do with the “Clip Start” and “Clip End” parameters because changing them either creates or fixes the problem depending on the scale. Solution: Although this might be normal because of the way it is programed, I see a relatively easy solution. The first solution for the user is to change the “Clip Start” value to a higher value when working with large scenes where the “Clip End” value is already set to a high value. Just changing the “Clip Start” value from 0.01m to 0.5m fixed the problem in the test project. As a solution, from a programming point of view, rendering the large and far objects from different lists with a higher “Clip Start” would be a solution. If rendering all objects works correctly by changing the “Clip Start” parameter manually, it should work when rendering different groups of objects. This is what I would call an adaptive solution. It adjusts the clipping parameters based on the objects size and distance to ensure a better rendering. The clipping parameters are set for all objects, but if adjust them for each object or (group of objects), you are going to get the best result for each object. I have not seen the code yet, but I’m trying to propose a realistic solution from my user and developer's point of view. Maybe it is not possible because of the z-buffer settings. I presume there must be a solution in terms of programing. [LargeSceneInconsistentVisibility.blend](https://archive.blender.org/developer/F10039303/LargeSceneInconsistentVisibility.blend) Clip Start 0.01m {[F10039304](https://archive.blender.org/developer/F10039304/ClipStart_0_01m.png) size=full} Clip Start 0.5m {[F10039307](https://archive.blender.org/developer/F10039307/ClipStart_0_5m.png) size=full}

Sebastien Larocque commented

2021-04-26 16:09:56 +02:00

Added subscriber: @SebBlender

Falk David commented

2021-04-26 19:25:28 +02:00

Added subscriber: @filedescriptor

Falk David commented

2021-04-26 19:25:28 +02:00

Changed status from 'Needs Triage' to: 'Archived'

Falk David closed this issue

2021-04-26 19:25:28 +02:00

Falk David commented

2021-04-26 19:25:28 +02:00

Unfortunately, I will have to close this because this does not classify as a bug. We have strict rules on the bug tracker as to what is considered a bug and what is not. Z-buffer artifacts due to Clip Start/Clip End values are well known and documented in the manual (see https://docs.blender.org/manual/en/latest/troubleshooting/3d_view.html#depth-buffer-glitches).

Sign in to join this conversation.

No Label

Download

What's New

Blender Studio

Manual

Developers Blog

Documentation

Benchmark

Blender Conference

Development Fund

One-time Donations

Inconsistent visibility in the viewport for large scenes #87834