Circular profile change for 1.12.2

In 1.12.2, the beginning and end of cut circular profiles will be on the analytical circle instead of the generated mesh. This can be seen most clearly on the attached cylinder image. This change should improve the constancy of cylinders and tori at low LODs.

Please check your content in Beta, especially content with cylinders and tori, and verify that it still looks stunning.

Doesn't that mean the lowest LOD is now more detailed and thus requires more resources? This seems counter-productive to me, I'd rather have it go into a hexagon if it has to in order to maintain performance, especially on smaller items (that are not small enough to be removed entirely by the LOD filter).

It doesn't look to me that there is any difference in the number of polygons in the two versions. It depends exactly how they are cut up though. I'll be checking some things in preview later tonight.

Yes it does have more facets now but at the cost at looking much better. LODs start at 8 sides not including top and bottom, then 16, then 32. The LODs before where 6 , 9, 15, 24. Rather Ugly number to work with except for the last one.

Have you ever tried playing SL on the lowest Detail? *ick.* So the Lowest LOD for a cylinder before had a facet (triangle) count of 24, now it has 32. not much to worry about. Truely this is a great improvement in the look of SL. A few thousand more trianlge to render in a sence does not cause much of a performnce hit. Even at lower detail settings it look better now. Now the LOD blend much better as a result.

Spheres still follow the old 6, 9, 15, 24 method.

The amount of polys between old and new are almost negligible -- my only worry is that it appears in the first image that having the cut suddenly misaligns it with what's below it.

Dan: This is my concern. A lot of us have built content depending on the alignment the way that LOD tesselates.... This was a problem in 1.10 that caused seams on all sorts of things to suddenly show up.

I'm showing signs of it here: things that used to line up and show no seams, may indeed after this change.

Could you tell me if you believe this is simply a cylinder-vs-sphere LOD calculation disparity that i'm seeing, or if it could happen within cylinders...

Problem is, though, due to the way it's been done in the past, many folks may have certainly aligned cylinders with spheres trying to 'work within the system' of LOD in the past -- those items may be broken now.

Sorry for the UI in screenshot, and I'll do more research on this later, but I think it is something that needs some illumination.

And yup, here it is.

Tailip of our housecat av is a sphere. Body of the tail is a torus. New seams and misalignments / disparities are showing up in 1.12.2.

Same tailtip in 1.12.1 - as you can see, there's stil a seam, but the faces line up.

Ok actualy i have already noticed spheres doing this, this is what happens to our avatars eyes on low lod levels, two spheres, a cut and a non cut, would end up with the non cut reducing to very low levels and the 'cut' reducing to the same number of poly's as it should be given its size, but the 3d coordinates of the sides that were actually cut, were created not 'within' the lod cut, but instead against the geometric ideal, causing the 'inner' slightly smaller, and cut sphere, to actually end up sticking out of the outer sphere, which had been LOD reduced more angularly...

Changing the other shapes to match this behavior itself is not initially bad but i think there needs to be some attention paid in that spheres really should behave to the LOD basically the same way torii and cylanders do as they are often used interchangably to create naturally smoothed and rounded shapes...

I.e. its actually BETTER for this that the cutting for all three shapes will now work in the same way (whereas spheres used to do this alone while the other shapes did not)... the issue is that the actual LOD culling of the spheres should also match the LOD of the cylanders as well, so that they can be aligned properly as this is what many many people do when building rounded objects...

Basically

change a: cut adhereing to geometric ideal
change b: LOD tesselation level changes

all three shapes, cylanders, torii, and spheres, should behave 'roughly' the same on both points...

Initially it was

spheres: a
cylanders: none
torii: none

now it seems like its

spheres: a
cylanders: a,b
torii: a,b

I think what needs to happen is that all three shapes, since they are used to align, should all have both of those factors, or they should all be missing one or the other, i.e. be kept in parity...

Ideally, just adding b in to the sphere would accomplish this, or less ideally removing b from cylanders and torii...

At least this is what i think is going on... In the end you should be able to make say a 3/4 cut 'medicine pill' with two spheres, and a cylander in the middle and it should be LOD zoomable/pannable etc and not show any seams.... thats by in large what people want, regardless of how 'round' it is at any given client setting etc...

This, I need to highlight, as being the crux of the issue. So, seconded.

Yep, I'm getting it too. Cut spheres and cut cylinders don't line up properly in 1.12.2. Ditto cut tori and cut cylinders.

This one the cylinder is red, the torus in white shiny:

Thirded.

Wow. Similarly to before, on your buildings, Seifert, this is VERY evident.

Did you bug report it, maybe with a ref to this thread? ... Wanna see if we can get Dan's input on this, since he did "RFC" it in the initiation of the thread.

Just bug reported.

So are we saying spheres need to be updated the same way as cylinders? And that is the bug? Which I belive they should. A sphere still has 6, 9, 15, 24, sides. That is if squash it flat on its Local X axis

If spheres are *not* set to the same lod/tesselation profile as cylanders/torii actual smooth curved objects are basically a literal impossibility, i.e. SL will be incapable of using spheres to render rounded corners to built objects, and there is no other prim shape that can.

Torus.
Speres will not be your only problem. here is a torus which also has 15 steps.

So which way do we want them to go? 15 steps or 16?

16 is better than 15. Divisible by 4 is much more useful.

Having said that, consistency between the different prim types is more important still.

But if you think about it, if you're at the lowest LOD then it's because you need all the performance you can get, at which point lower is still better even if it's only a small amount of difference. With enough prims on screen a cut of 5% could make all the difference. If looks are important then have smaller steps in the LOD, especially at higher levels. Hell, have it go higher in general, if machines can't handle it now, they will eventually!

In light of the horrible difference between spheres and cylinders/toruses, I'd vote to put it back, and do something else instead.

I mean, playing with LOD seems like wasted effort unless it has a performance boost, but from what I hear all it seems to do is add more polygons to render when lower end or overwhelmed machines are struggling the most!
LOD doesn't even seem to be too much of a performance hog anyway, occlussion culling is in need of performance tweaking for more speed

Okay, bad news the LOD change was put through onto main grid with release of 1.12.1.12.

Just went on and married a half sphere to a cylinder

The LoD settings in preferences don't specify the lowest level of detail that objects are displayed on your computer, they control how far away from you the objects are when they show that level. The lowest level of detail is seen by everyone, at some distance or another, and for some objects (such as spectacles) even fairly high settings will still leave them visibly distorted at modest distances.

The change also has broken some content of mine. The texturing on a cut cylinder's round face is now pretty wonky... go look at the signs on the base of the statue in Suffugium's center square (at the telehub).

Yep my space house is broke now. The corners are half tube to 1/4 cylinder. I would imagine it will be a fun morning in Current Version forum. Lot of unhappy designers/builders/owners. It is going to be interesting to see who approved releasing it to main grid.

It does not matter where you are at zooming in and out. They never mesh anymore.

Doesn't this imply a hierarchical decision making system of which there is no evidence?

I just dont understand this. We detailed it immediately. We bug reported... But it went through anyways -

This does NOT, I repeat NOT only affect the lowest LOD settings. I have my detail set to the maximum (even the 'override maximum' in the xml file) - and this still happens when zoomed in all the way.

I dont understand why they keep changing LOD like this. Wasn't this supposed to make things look better?

This doesn't make things run faster -or- look better.