[BUG-100792] Linking and/or shift+copying large linked mesh builds results in most angular data being skewed.

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Steps to Reproduce

selecting all the pieces after positioning them, choosing the master prim and then using the key command 'ctrl+l'. This problem happens either with the standard SL client, or Firestorm. I suspect the reason this is an issue is because I'm using large, very angular pieces where the slightest misalignment will show up dramatically.

Actual Behavior

When linking large mesh items that I've created/uploaded into world, very angular building structures with pieces 10 meters in length and link distances over 20+ meters, The angle of the individual shapes will be altered either +/- 0.1° or 0.05° along a single channel. For example, say a piece in a linkset has the following angles set: <270.0000, 0.0000, 180.0000>
After linking, that piece and several others with the same orientation will read: <270.0000, 0.1000, 179.9500> Those kinds of angle errors equate to 8.7mm and 4.3mm gaps respectively when dealing with a 10 meter span and show up dramatically after.

This happens when linking the pieces in world, or shift/copying a 'corrected' linkset.

If the linkset is unlinked, then all the pieces snap back to their correct angular orientation.

Expected Behavior

I was expecting the linked items to remain in the angular position they were set at before I linked them.

Other information

I'm uploading a large structure kit for buyers to assemble, the first version, two years prior, never had this issue. As it stands now a user will have to assemble the pieces to their liking, link, then /readjust them all a second time/ as linking the pieces will skew them all off angle enough to be noticeable. The fact that it's either only +/- 0.1° or °0.05 degrees off axis on a random rotation channel, regardless of what I've uploaded, has got me thinking this is some server-side code error that's making itself obvious.

I would be happy to demonstrate the problem for anyone that asks.

Original Jira Fields

| Field | Value | | ------------- | ------------- | | Issue | BUG-100792 | | Summary | Linking and/or shift+copying large linked mesh builds results in most angular data being skewed. | | Type | Bug | | Priority | Unset | | Status | Accepted | | Resolution | Accepted | | Created at | 2017-06-06T13:38:13Z | | Updated at | 2017-06-09T22:45:59Z | ``` { 'Business Unit': ['Platform'], 'Date of First Response': '2017-06-06T12:25:25.469-0500', "Is there anything you'd like to add?": "I'm uploading a large structure kit for buyers to assemble, the first version, two years prior, never had this issue. As it stands now a user will have to assemble the pieces to their liking, link, then -readjust- them all a second time as linking the pieces will skew them all off angle enough to be noticeable. The fact that it's either only +/- 0.1° or °0.05 degrees off axis on a random rotation channel, regardless of what I've uploaded, has got me thinking this is some server-side code error that's making itself obvious. \r\n\r\nI would be happy to demonstrate the problem for anyone that asks. ", 'ReOpened Count': 0.0, 'Severity': 'Unset', 'System': 'SL Viewer', 'Target Viewer Version': 'viewer-development', 'What just happened?': "When linking large mesh items that I've created/uploaded into world, very angular building structures with pieces 10 meters in length and link distances over 20+ meters, The angle of the individual shapes will be altered either +/- 0.1° or 0.05° along a single channel. For example, say a piece in a linkset has the following angles set: <270.0000, 0.0000, 180.0000> \r\nAfter linking, that piece and several others with the same orientation will read: <270.0000, 0.1000, 179.9500>\r\nThose kinds of angle errors equate to 8.7mm and 4.3mm gaps respectively when dealing with a 10 meter span and show up dramatically after.\r\n\r\nThis happens when linking the pieces in world, or shift/copying a 'corrected' linkset.", 'What were you doing when it happened?': "I wasn't 'doing' anything other than selecting all the pieces after positioning them, choosing the master prim and then using the key command 'ctrl+l'. This problem happens either with the standard SL client, or Firestorm. ", 'What were you expecting to happen instead?': 'I was expecting the linked items to remain in the angular position they were set at before I linked them. ', 'Where': 'http://maps.secondlife.com/secondlife/Alethia%20Island/109/102/2502', } ```

[sl-service-account]

Kyle Linden commented at 2017-06-06T17:25:25Z

Hi Kaltezar,

It looks like you are on a several months old 5.0.0 Second Life viewer build.

Please install the latest version from https://get.secondlife.com

Then let us know if you can still reproduce this issue.

Thanks!

[sl-service-account]

kaltezar.chickenwing commented at 2017-06-07T00:34:25Z

Downloaded/installed/used latest viewer, problem still remains.
Highly suspect this is server-side, not client-side as other residents in world are able to not only see the problem demonstrated, but reproduce it themselves as well with the same items and circumstances, regardless of viewer.

[sl-service-account]

Whirly Fizzle commented at 2017-06-08T16:33:13Z

This looks like the same problem filed at https://jira.phoenixviewer.com/browse/FIRE-21238 I have the repro items for FIRE-21238 if a Linden needs it.

[sl-service-account]

kaltezar.chickenwing commented at 2017-06-09T00:04:14Z, updated at 2017-06-09T00:10:43Z

To Whirly,

That's looking very much like a connected issue - I noted in the video for the linked item the Y and Z axis were 1.14999 and 180.0999 Respectively, once the position was slightly shifted, those values changed to 1.25 and 180. Once again following the +/- 0.1° and/or 0.05° values that are injected at random.

Something tells me this is a fundamental bug in the code base as it's seen across clients, and has to do with how the root object stores alignment data of it's child objects. Comments please Lindens? Considering mesh is becoming much of a mainstay of SL, and as more people upload finely tuned and aligned, multi-part mesh items, making sure they stay lined up to how they're intended should be a pretty important.

[sl-service-account]

Whirly Fizzle commented at 2017-06-09T12:51:18Z, updated at 2017-06-09T12:51:40Z

Found an old issue that looks very similar too. VWR-15912 - Positions of prims changed by linking.

[sl-service-account]

Kyle Linden commented at 2017-06-09T22:41:24Z

Confirmed this is reproducible. Subtle offsets are visible when comparing shift+drag based copies of complex linksets.