Motion Blur glitches, the further an object is placed from the world origin (even with no motion) #71396

New Issue

Ru Cook · 2019-11-06T22:07:06+01:00

Ru Cook commented

2019-11-06 22:07:06 +01:00

System Information
Mac Os 10.14.5
Radeon Rx580

Blender 2.8 & 2.81 Beta (5/11/19 build)

Objects are seriously corrupted when the motion blur checkbox is ticked, even when there is no camera or object motion.

I have attached a simple project with only a Cube, Camera & light... & placed it 500,000m from the world origin on the Y-axis.

The image is distorted in rendered camera view...moving the cube backwards towards the world origin fixes the issue at around 50,000m

Moving the object further away (try adding a zero to push the cube 1,000,000 from the world origin) distort the object more.

Switching off motion blur on the (static!) camera restores the image quality.

I'm doing a space animation with some large distances involved, & this bug has just bitten me. I'd appreciated if others could confirm.
Motion Blur Draw Distance Test.blend

**System Information** Mac Os 10.14.5 Radeon Rx580 Blender 2.8 & 2.81 Beta (5/11/19 build) Objects are seriously corrupted when the motion blur checkbox is ticked, even when there is no camera or object motion. I have attached a simple project with only a Cube, Camera & light... & placed it 500,000m from the world origin on the Y-axis. The image is distorted in rendered camera view...moving the cube backwards towards the world origin fixes the issue at around 50,000m Moving the object further away (try adding a zero to push the cube 1,000,000 from the world origin) distort the object more. Switching off motion blur on the (static!) camera restores the image quality. I'm doing a space animation with some large distances involved, & this bug has just bitten me. I'd appreciated if others could confirm. [Motion Blur Draw Distance Test.blend](https://archive.blender.org/developer/F7965803/Motion_Blur_Draw_Distance_Test.blend) ![Screenshot 2019-11-06 at 21.06.37.png](https://archive.blender.org/developer/F7965834/Screenshot_2019-11-06_at_21.06.37.png)

Ru Cook commented

2019-11-06 22:07:06 +01:00

Added subscriber: @Samsara_71

Ru Cook changed title from ~~Motion Blur glitches, the further object is placed from the world origin.~~ to Motion Blur glitches, the further an object is placed from the world origin.

2019-11-06 22:09:40 +01:00

Ru Cook changed title from ~~Motion Blur glitches, the further an object is placed from the world origin.~~ to Motion Blur glitches, the further an object is placed from the world origin (even with no motion)

2019-11-06 22:13:50 +01:00

Philipp Oeser commented

2019-11-06 23:08:39 +01:00

Added subscribers: @fclem, @Jeroen-Bakker, @lichtwerk

Philipp Oeser commented

2019-11-06 23:08:39 +01:00

Can confirm the behavior, but lots of viewport drawing gets really glitchy that far off of the origin [that point light also gets funky if you get close to it ;)].

@fclem, @Jeroen-Bakker: Assume this is a precission error [that cannot really be avoided]?

Can confirm the behavior, but lots of viewport drawing gets really glitchy that far off of the origin [that point light also gets funky if you get close to it ;)]. @fclem, @Jeroen-Bakker: Assume this is a precission error [that cannot really be avoided]?

Philipp Oeser commented

2019-11-06 23:10:15 +01:00

This comment was removed by @lichtwerk

*This comment was removed by @lichtwerk*

Ru Cook commented

2019-11-06 23:11:17 +01:00

It glitches on the render too sadly, not just the viewport...I had a massive scene built, a long way from the world origin, & couldn't work out why it looked so bad until I switched motion blur 'off'

Ru Cook commented

2019-11-06 23:16:52 +01:00

Are there any workarounds for this?

I've build a huge camera fly through on a space-scene for a music video that i'm loathed to change, but it seems the render is just degrading the further objects get from the world origin, even when the camera just settles on an object (when motion blur is switched on)

I had no Idea it would be an issue, as I thought distance in Blender would just be an arbitrary concept ! :)

Any thoughts ?

Are there any workarounds for this? I've build a huge camera fly through on a space-scene for a music video that i'm loathed to change, but it seems the render is just degrading the further objects get from the world origin, even when the camera just settles on an object (when motion blur is switched on) I had no Idea it would be an issue, as I thought distance in Blender would just be an arbitrary concept ! :) Any thoughts ?

Clément Foucault commented

2019-11-07 14:14:38 +01:00

This is a precision error but I don't know how much we can do about it. I'll investigate

Do note that the camera motion blur does not work well if the camera is parented but in this case, it does not matter.

This is a precision error but I don't know how much we can do about it. I'll investigate Do note that the camera motion blur does not work well if the camera is parented but in this case, it does not matter.

Firepal commented

2019-11-07 17:16:41 +01:00

Added subscriber: @Firepal

Firepal commented

2019-11-07 17:16:41 +01:00

Changing the "Clip Start" values on the light and camera to higher values helps alleviate the lack of precision in their depth buffers slightly.
For instance, changing the camera's Clip Start value to 3 makes the glitching much less severe (but still present), and setting the light's Clip Start value to 0.5 and Bias to 5 eliminates all the shadowy noise.

The issue is that objects out of the Clip Start and End range will be cut off, so this is not an end-all be-all fix.
I would be pleasantly surprised to see a fix for this.

Changing the "Clip Start" values on the light and camera to higher values helps alleviate the lack of precision in their depth buffers **slightly**. For instance, changing the camera's Clip Start value to 3 makes the glitching much less severe (but still present), and setting the light's Clip Start value to 0.5 and Bias to 5 eliminates all the shadowy noise. ![aaaaaaaaaaaaaaacube.png](https://archive.blender.org/developer/F7976167/aaaaaaaaaaaaaaacube.png) The issue is that objects out of the Clip Start and End range will be cut off, so this is not an end-all be-all fix. I would be pleasantly surprised to see a fix for this.

Philipp Oeser removed the

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Motion Blur glitches, the further an object is placed from the world origin (even with no motion) #71396