Is anyone else having prims go invisible?

[Brookston Holiday]

In the latest project viewer whenever I stretch a prim to a large size say ~50 meters or more, it turns invisible.  Is this happening to anyone else?  I can't seem to find a JIRA about it, and want to know if anyone else has seen this behaviour.  

[Drongle McMahon]

No problem with viewer 223637. I just stretched a mesh cube to 64x64x64 with no problem. Are you sure you aren't inside it?

[Brookston Holiday]

Sorry, it's regular, not mesh prims, and it seems that only some are effected.  In the picture, the prim lower left is large but visible, the other two are invisible.  The texture turns visible again if I move them or resize them, but after a second they turn invisible again, and you can only tell they are there by editing them so the outline is visible or flying into them you bump off.  

 

[Drongle McMahon]

I went and had a look at that sim. I found (at least) three of your boxes there. Only one was visible. When I teleported or flew away far enough that they were out of draw distance, then came back again, they all appeared as they entered draw diostance, but then, as I approached (LOD switch?) a random selection (including sometimes none and sometimes all) suddenly became invisible. I could not see the same phenomenon in any other sims, even in Dan's sim full of huge ducks. Is it possible this is server-related? Might be worth asking a Linden to restart the sim ans see if the behaviour persists. If so, it definately needs to have a jira. As you say, you can select them, so it's nothing to do with the 0,0,0 bug.

PS. I went to Mesh Sandbox 33 (pretty empty) and made some large boxes. I did not see the vanishing effect at all. However, when I put three large boxes on Mesh Sandbox 11, where yours are, then they were affected. This sim is about half "full" with >7000 objects. Perhaps it is the fullness of the sim that provides the conditions for manifestation of this bug. Although Dan's duck-full sim is packed, it isn't very many objects, by comparison.

[linkin Slate]

 i have also  had kinda same thing happened to me this  week, some shoes i been working on imported. and  seems the lod switch when i zoom close  they go invisable , but if i wear them  then  they seem uneffected, i tried a pair i uploaded weeks ago they seem effected also  so wasnt  anyhting to do with  uploading. seems like a lod switch issue.

[linkin Slate]

Guess you was  talking about   Prims and not mesh. sorry   maybe my mesh problem is a different  issuse then, but it does seem to  happen at lod switch and this just seemed to have just started.

[Drongle McMahon]

Linkin, are you using the automatic LOD mesh generation? This will often have quite bad effects. It is generally well worth making the LOD meshes yourself so that you can ensure the boundaries of the mesh are preserved where that is essential. If you did make your own, are you sure the normals are correct?

[linkin Slate]

ya i been just doing the auto, but with most of my tests i been most on the  shape and looks , this time i droped the poly count down to get lower prim costs seems that effects the lods lower you go bigger  the changes, guess ill have to dig in to maken my own , just off heand if you have time to answer  its a 25 % drop right for each lod ?

[DanielRavenNest Noe]

My understanding is each LOD should be half the polgon count of the next higher one.  That goes along with texture loading, which goes in steps of "times one half" depending on distance.  Thus the 3rd LOD would be 1/8 the polgon count.

Doing mesh for another graphics engine we were told below 300 triangles it was not worth making lower LODs.  The reason was it takes time to *switch* from one LOD to the next, and at some point that ends up taking longer than loading a small model saves you. 

It would be helpful to know if for the SL graphics engine and server streaming if there is a lower practical limit like that.  In other words, below what triangle count does it stop saving you anything?  If such a limit exists, then the remaining LOD files you select on upload would just be more copies of the lowest practical one.

[Drongle McMahon]

I can tell you the current situation, with the warning that it may very well change. At least it is promised that the extra cost penalty for not having good (eg 1/4) LOD reductions, will get more stringent. Right now, the default reduction is 1/4 per LOD step. It does not stop after it reaches a limit until it gets as low as two triangles (for the two sides of a flat triangle).

However, you can override this either by setting the triangle limit for each generated LOD in the upload dialog, or by supplying files with more (or less) triangles. It will not, of course, let you have more triangles in a lower LOD, but you can make them all the same. There is a substantial prim cost penalty (and probably upload cost) which is going to get worse.

So it all depends what you are doing. If your mesh is very simple (eg a flat door, 12 triangles) the cost is low even if you have the same at all levels, and that prevents it becoming a triangle! For larger or more detailed meshes, the penalty will provide an overwhelming motivation to have big LOD reduction factors.

[Snow Sweetwater]

I'm having a problem somewhat related... my prims are turning invisible only when I edit them.  This makes building really difficult.  Anyone else having the same issue?  Any suggestions?  I've gone thorugh all my settings and searched for this problem and haven't found any help.