A Rant about Prim Drift

OK, I'm a perfectionist. Now heaven knows that building in SL is definitely not for those with any lack of patience, but must they throw prim drift onto us, too?

I would like to know what causes this, and how the Lindens can fix it.

I will fix my build perfectly. All done with it. Got it all squared away perfectly. Lock it. Leave overnight.

Come back the next day. There's a seam showing! One that wasn't showing the night before. I unlock that piece. Often unlocking the entire build in the process, regardless of how long I wait after clicking "edit linked item" before clicking "unlink."

(And the reason I unlink it is if you actually edit the linked piece while it is still linked, like as not it will bounce back anyway, or even more oddly, will act in some way it doesn't act at all if you unlink it then edit it. You might change an 89.5 to a 90.00, and unlinked, it will do just that - linked, it will bounce all the hell over creation and end up backwards and upside down no matter what you do.)

So I unlink the wall, and discover that in the night it has gone from being 90 degrees to 89.5 degrees. Thus creating the seam.

Fix it again. Next day, another place has decided to move its rotation, or switch its position somehow. I'm busy working on the accessories, and I have to stop and redo parts of the house. All the time!

This is like doing the dishes and going to bed and waking up to discover that some of the dishes have redirtied themselves and hopped back into the sink. Very discouraging. You almost have to be a martyr to stick with it.

Why? Why does it do this?

Is this I'm not working slowly enough, and my computer shows stuff theirs hasn't really done? But this doesn't seem possible, because I would never put in 89.5 as a rotation angle. But could this somehow be the problem?

The only thing I have read to explain prim drift was something about how the system itself has more decimal places - we see 217.576, but it is actually putting in 217.5765 or something.

Is that true?

If so, why can't they fix that? Is there some reason why they need to have that secret extra decimal place that messes builders up?

And if that isn't the case, why the prim drift?

Given this prim drift, you are lucky to get ANY build finished without seams.

I really am about the the end of my perfectionist rope with this prim drift - over which I apparently have no control.

Is there some way to control it? Anything I can do?

coco

Not a whole lot you can do about it, except go in and edit it later. Think of it as your house settling and having to make repairs.

I just made a decent sized house for my girl and I and placing is soo much fun. Any kind of lag can throw alignment out the window. Pieces that were perfect will end up out of place, etc.

Especially when you have your house in sections and your rotating the whole thing. Lag hits and you'll find that the sections lose alignment. I ended up placing and deleting until it finally looked like all the sections were oriented correctly.

No, it's broken and LL doesn't know why either.

Avoid rotations if you can (square is "in" this week), snap to grid as much as you can, avoid the third decimal place (shift-X is your friend). Wait for SL2; they've stopped trying to fix SL1.

I know about shift-x, and I'll try the other tips. I know about rotating whole linked houses, too, and do it VERY slowly, with full expectation of having to delete it and try it again.

coco

Prim drift is caused by something called floating point precision loss - it's a technical problem that is a universal issue on modern computer processors.

Once the Pentium4's are completely removed from the Sim server line, LL might be able to use double precision floats; without a performance hit (which will alleviate the problem somewhat)

LL most definetely knows the cause of the problem - just not how to solve it without causing serious performance issues with sims; at least not until all the sims are 64bit anyway.

-Adam

Wow, Adam! That's a nifty explanation, course as usual, I didn't understand it even after reading it three times. But I gather there might be some hope for this problem in the future maybe.

Meanwhile, I notice if I just keep fixing it over and over, eventually it stays. And yes, I have always thought of it as the house "settling". This whole thing, with the way my builds are, I would estimate adds about 15-20% more time to the build process for me. (I started to say 25%, but I want to be conservative on it, it might just seem more time-consuming than it is.)

coco