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Cycles is being less and less accurate when moving away from the center of the scene
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Description

System Information
Windows 8.1, Windows 7

Blender Version
Broken: 26.9 official
Worked: none

Short description of error
Cycle is being less and less accurate when moving away from the center of the scene

Exact steps for others to reproduce the error
I've put a simple setup in the .blend file with 2 cameras and the sames obj arrangement in front of those cameras.
When you render at frame 1 (the camera close the the center), the render is good.
But when you switch to the 2de camera at frame 50 witch is far from the center, the render become glitchy.

You can move all the obj on the X axis with cycle preview "on" to see the gliches appears in realtime.

I've tried to switch from "Dynamic BVH" to "Static BVH" but there is no differences.
No differences either when switching between GPU and CPU

Details

Type
Bug

Event Timeline

Ronan Zeegers (ronan) added a project: Cycles.
Ronan Zeegers (ronan) set Type to Bug.
Ronan Zeegers (ronan) created this task.
Ronan Zeegers (ronan) raised the priority of this task from to Needs Triage by Developer.

How can I attached the files??

The render when the camera is close to the center:
close image
The render when the camera is far to the center:
far image

the .blend file:
CycleAccuracyBUG.blend

I'v forget: for the hardware, I'm using a Geforce 780 and a 560Ti

Thomas Dinges (dingto) renamed this task from Cycle is being less and less accurate when moving away from the center of the scene to Cycles is being less and less accurate when moving away from the center of the scene.Feb 2 2014, 12:41 PM
Thomas Dinges (dingto) triaged this task as Confirmed, Medium priority.

I can confirm the bug in the attached file but can't reproduce the issue with a new file built from scratch yet, even if rendering 5 km away from the center.

Ronan Zeegers (ronan) added a comment.EditedFeb 2 2014, 3:33 PM

Try with a cube with Dimensions: 0.100/0.100/0.100, Location X:10000/Y:0/Z:0 and the camera around X:10000.31738/Y:-0.277727/Z:0.18018

This is known limitation of float precision. In general they're quite tricky to resolve, but maybe there's some way to do it without major pain in Cycles.

There's no easy solution, we would like to improve accuracy but it's not considered a bug.

Ronan Zeegers (ronan) added a comment.EditedFeb 3 2014, 2:52 PM

Why not make the "center" of Cycles's computation on the camera's position instead of the scene. This would solve the problem no?
Right not, I have to do that by parenting all the objetcs in the scene to an empty and recenter all my cameras cuts/movements one by one. Wihch is really painfull..

I've noticed that if you switch camera's lens from "perspective" to "panoramic" those precision artifacts are reduced when seen through transparent shader or completely disappear when seen directly from camera. Can anyone explain why is it so?