| Jacques Lucke (JacquesLucke) |
| nullpoint | |
| Jan 8 2019, 5:45 AM |
| Brecht Van Lommel (brecht) |
| Charlie Jolly (charlie) |
| Jacques Lucke (JacquesLucke) |
| nullpoint |
Blender Version
2.79b
Hello!
There is a problem in blender.
Sometimes if you rotate an object, and set apply "rotation and scale" , the dimensions of object will be changed strangely.
I made a gif, that will help understanding the problem. Also, i attached the blend file.
https://giphy.com/gifs/Ph5syOI0IO6CK9pOM9
Thank you!
Next time, please upload the .gif directly here and not only share a link to it.
It is hard to see what you are doing exactly due to the low resolution.
It looks like you mean the problem that the dimension becomes 1.80002.
While I'm not absolutely sure why that happens after a 180 degree rotation, things like that cannot be avoided due to inaccuracies in the internal number representation.
I would not consider this a bug.
If there is something else to this issue, please reopen it.
I dont know why this bugreport is closed.
This is a huge problem in blender long time ago, in results, the working make extremly slow, and full impossible to make precision works. This is a thing which is needed to be repair. In architecture, precision is mandatory.
Please reopen this case, maybe somebody can help.
Thank you.
I'm sorry but this is just the way it works now, we are limited by floating point precision. CAD software often uses increased precision at the cost of performance, but changing Blender to support this would take months/years of work and not necessarily be a good trade-off for other work.
In any case, this is not a bug, no matter how important you consider it. The same thing happens in other 3D software.
@nullpoint
1.80002cm has an error of 0.0002 cm which is tiny and is 2 micrometers. A human hair is typically about 50 micrometers.
This is purely an issue of how computers store and process numbers. See: https://en.wikipedia.org/wiki/Floating-point_arithmetic#Accuracy_problems
Blender could hide the inaccuracy and just show 1.8 for example but the actual number would be the same.
Thank you the answers guys.
The object itself is deformed after the rotation. If you go in edit mode and select a vertex, you will see the vertex coordinates are wrong. If you set the vertex location to the expected coordinate, the mesh will be good again. Of course until the next rotation :D This problem is results the snapping too, and after some iteration, de differenties are added together.
Affected the duplicate too. Example. You have an object, which is in the Y axis perfect 18mm thick now :) You duplicated and move on the y axis, 18mm. And repeat this like 50times, the last object will be defected. Interesting.
Beside, this problems is very hectic, sometimes arrives after the 4th object rotation, sometimes only the 50th.