Why do textures become misaligned?

[Jennifer Boyle]

I have multiple large prims that are parts of buildings. There are good reasons why they are separate, adjacent prims. They are textured with the same texture. Picture a tiled floor. I align the textures perfectly using the "Align Planar Faces" feature of the editor. Then, I lock the prims. Months or a few years later, I look, and the textures are slightly misaligned. I can easily align them perfectly again using "Align Planar Faces."

Why do thye spontaneously become misaligned?

[Nalates Urriah]

You can look through the JIRA to see if there is a more definitive explanation of the why or a fix in progress.

It has been awhile since I dug into the 'things moving' problem. So, my memory may not be spot on.

As regions and their contents are saved (backed up?) and later reload on region restart round off errors creep in. Generally we see more problems with prims creeping. At high altitude it is worse. Old sims that haven't had some maintenance often have trees that float in the air... the older the higher they have floated.

The only work-around I remember is making sure prims avoid having dimensions that use the third and fourth decimal places. There is also the position (X,Y,Z) values.

Obviously it is a pain to build with sizes and positions limited to the nearest centimeter. And there are the digital math problems too. Its the floating point problem of representing some real numbers. (Ref)

You are the first to mention texture creep that I know of. But, if others are seeing the problem then there is likely a JIRA filed.

You can attend the Tuesday noon Linden meeting in Denby and ask a Linden about the problem.