[BUG-7639] Prim precision

[sl-service-account]

Steps to Reproduce

Building

Actual Behavior

Two issues that are probably related: Object positions and rotations shift over time, and objects that are aligned with each other as precisely as possible still show noticeable gaps or overlaps.

Expected Behavior

I expect my objects to stay where I place them and I expect to be able to place them with the level of precision one should expect in the 21st century.

Other information

I know this will be closed down as a duplicate right away - I'm perfectly aware it's vbeen reported before.

But that's my poinnt really. Prim drift and prim gaps are two of the most crucial bugs a builder has to fight against and they're still here after more than 11 years!

The issue has become more critical recebntly, partly because people expect higher graphics quality these days but mostly because quality meshes tend to be even more vulnerable than prim builds.

Original Jira Fields

| Field | Value | | ------------- | ------------- | | Issue | BUG-7639 | | Summary | Prim precision | | Type | Bug | | Priority | Unset | | Status | Needs More Info | | Resolution | Unresolved | | Reporter | ChinRey (chinrey) | | Created at | 2014-10-27T14:53:07Z | | Updated at | 2017-07-07T15:53:34Z | ``` { 'Business Unit': ['Platform'], 'Date of First Response': '2014-10-27T18:51:41.094-0500', "Is there anything you'd like to add?": "I know this will be closed down as a duplicate right away - I'm perfectly aware it's vbeen reported before.\r\n\r\nBut that's my poinnt really. Prim drift and prim gaps are two of the most crucial bugs a builder has to fight against and they're still here after more than 11 years!\r\n\r\nThe issue has become more critical recebntly, partly because people expect higher graphics quality these days but mostly because quality meshes tend to be even more vulnerable than prim builds.", 'Severity': 'Unset', 'System': 'SL Simulator', 'Target Viewer Version': 'viewer-development', 'What just happened?': 'Two issues that are probably related: Object positions and rotations shift over time, and objects that are aligned with each other as precisely as possible still show noticeable gaps or overlaps.', 'What were you doing when it happened?': 'Building', 'What were you expecting to happen instead?': 'I expect my objects to stay where I place them and I expect to be able to place them with the level of precision one should expect in the 21st century.', } ```

[sl-service-account]

Caleb Linden commented at 2014-10-27T23:51:41Z

Hi ChinRey,

What is the amount of drift that you are experiencing? If it's a small drift, it's a known issue.

Thanks, Caleb

[sl-service-account]

ChinRey commented at 2014-11-02T09:57:42Z

Yes, I know prim drift and prim gaps are known issues. I have struggled with the problem for as long as I have been a content creator in SL and from what older builders have told me, it has been here as long as SL has extisted.

But that inevitably brings up the question: Why has it never been fixed? And if it is impossible to correct, why hasn't LL come up with a proper explanation? This isn't a minor issue, this is a serious bug - one of the most important factors that limit the quality of the content we can make in and for SL!

I created this JIRA after yet and other long and tedious round of builders venting their frustrations at the Builder's Brewery chat. I don't remember the detail of the specific case that triggered the talk that time but here is an example that came up only a few minutes ago:

I was working on my builder platform at Coniston, resizing some prims in a linkset to fit a mesh to it. I selected one of the prims and the coordinates were 67.100,197.000,2003.100 as they should be. Suddenly, while I watched the figures, the y coordinate jumped to 196.990. I'm on a rather poor connection at the moment (my regular line is down so I have to use mobile broadband) so I wouldn't have been surprised if such a thing happened while I was editing but this was bero I had the chance to do that - I had just selected the prim to read the data and calculate its new size and position and hadn't had the chance to make any modifications to it whatsoever before it jumped out of position.

[sl-service-account]

Maestro Linden commented at 2014-11-03T19:14:16Z

Hi ChinRey, 1cm is a little extreme for drift. I can't make it happen when I use "Second Life 3.7.19 (295700) Oct 20 2014 16:07:52 (Second Life Release)" on Second Life Server 14.10.17.295641. Here's what I tried:

1. Rez a default box
2. Sit on the box (so it doesn't disappear when you move it)
3. Select the box, and open the build tool's Object tab
4. Type 67.1 for the position x-coordinate, and hit enter
5. Type 197 for the position y-coordinate, and hit enter
6. Type 2003.1 for the position z-coordinate, and hit enter
7. Save the 'position reporting script' (below) in the box
8. Touch the box, and verify that it has 0 'error' from the build tool coordinates
9. Stand up, and reselect the box
10. Observe that the position shown in the build tool is still <67.100, 197.000, 2003.100>
11. Log out, then log back in at the same place
12. Select the box. Observe that the position shown in the build tool is still <67.100, 197.000, 2003.100>
13. Restart the region
14. After the restart, select the box. Observe that the position shown in the build tool is still <67.100, 197.000, 2003.100>
15. touch the box and observe that error is still 0:

    [11:12] Object: My position: <67.10000, 197.00000, 2003.10000> [11:12] Object: Distance from target <67.10000, 197.00000, 2003.10000>: 0.000000

vector targetPos = <67.1, 197.0, 2003.1>;
default
{
    touch_start(integer total_number)
    {
        vector myPos = llGetPos();
        llSay(0, "My position: " + (string)myPos);
        llSay(0, "Distance from target position " + (string)targetPos + ": " + (string)llVecDist(targetPos,myPos));
    }
}

Can you be please describe how to trigger the 1cm drift to 196.990, in steps similar to what I have above?

[sl-service-account]

Mike Denneny commented at 2014-11-05T20:09:03Z

The only time I was getting prim shifts is when I rotated objects 180 degrees. I would notice they suddenly became 179.50 which would create gaps in the objects. I worked with andrew linden on this, but haven't really seen much of it since.

[sl-service-account]

Whirly Fizzle commented at 2014-11-05T20:23:17Z

Theres some repros for "prim drift" in the comments on STORM-1915 The STORM-1915 changes fixed some of the old "prim drift" problems but not all.

[sl-service-account]

Malin Sabra commented at 2016-11-28T16:56:22Z

I've had this issue recently also. I have fixed the back wall of my house 5 times in a week because they would shift the tiniest bit, enough to show lines going down the walls.

[sl-service-account]

Saeros Linden commented at 2017-07-07T00:42:59Z

Our apologies, it appears this jira has been a victim of a spammer. We’re cleaning up the offending comments, sorry for the mess!