how much does Display Weight impact lag?

[Jaauuwn]

I am trying to figure out why I have so much lag on a parcel where the Parcel land impact is less than 30% of the Parcel land capacity. I own multiple parcels in the region so the Parcel land impact is less than 2% of the overall region. I basically assume prim count is not the issue but for some objects when I check 'More Info' under the 'Object' tab the Display weights seem disproportionately large.

As example I have a simple non-scripted 2 prim object with the following weights:

Download = 0.1 / Physics = 0.2 / Server = 1.0 / Display = 3128

Does that Display weight of 3128 seem excessive? The object is just a framed painting.

Before I start deleting all items like this I would just like to ask how much I should be concerned about Display weight contributing to server lag and what could be considered a reasonable Display weight.  When I search this subject the only discussion I can find is where it concerns avatar attachments and not objects within a Sim.

If Display weight is a significant measure of Parcel performance shouldn't there be a summation of it under 'About land' just as with the total prim count?

Any help on understanding this would be appreciated. Thank you.

 

 

[Mollymews]

without seeing your parcel and stuff then things to look for

1) trees that use blended alphas and texture animation to wave the leaves. If so do you have more than one where depending on your camera angle the trees are stacked behind each other.  This combination can cause significant drops in FPS due to how OpenGL does Z-ordering of alphas.  And if this is so then do you also have shadows turned on ? Shadows are already quite taxing on the graphics card. Adding alpha texture animation taxes this further

2) objects with lots of large textures. The worst example being a different 1024x1024 texture for each surface. This can cause texture thrashing - textures being swapped in and out of graphics card memory

3) a mesh object that is malformed. A single malformed mesh object can bring a viewer to a standstill (including crashing the viewer). A malformed object may not even be visible. A way to detect the direction where such a object might be, is to rotate your view and watch the FPS. If the FPS drops in a direction and recovers in the opposite direction, then its something within the view (the viewer interest list) in the FPS drop direction

4) a scripted physical object which is stuck somewhere and is battering away against other objects on a fast cycle. This can turn the server, and subsequently the viewer, to mud also

[ChinRey]

4 hours ago, Jaauuwn said:

I am trying to figure out why I have so much lag on a parcel where the Parcel land impact is less than 30% of the Parcel land capacity.

Land impact is all about server and bandwidth load since LL couldn't care less about client side lag back when they made the LI system. (They know better know and are working on and off on an upgraded system.) There is some correlation of course but not much.

In addition to what Mollymews already mentioned:

1. Multiple high poly meshes.
2. Multiple sculpts, especially if they are large. Sculpt lag isn't nearly as serious as many people claim but it can still be a problem
3. Glow, animated textures, light emitters etc., etc. don't usually add much lag but it adds up and can be a problem if there's a lot of it going on
4. Particles  - same there: A few of them won't make a difference, but lots of them - especially if they are alphas (for example fog and smoke effects) - can cause problem for even the most powerful computer.
5. Avatars. Fitted mesh tends to be very high poly and heavily textured, and the LoD system is broken for them.
6. Large stretches of uncovered ground. This may come as a surprise but an empty sim with a perfectly flat ground can actually be quite laggy. This is not a roblem very often since usually most of the ground mesh is hidden by terraforming and objects but it is something to watch out for.

 

5 hours ago, Jaauuwn said:

Does that Display weight of 3128 seem excessive? The object is just a framed painting.

That depends on how you see it. 3128 render weight will reduce your frame rate enough that it's measurable but probably not noticeable. It is six 1024x0124 textures though and that's far more than such an object can possibly need. If this is typical for what you have on your land, you will have lag problems, if it's a one-off extreme case, there shouldn't be anything to worry about.

Beyond that I'm not quite sure what to say about such an extreme case of over-texturing. I think we should accept it if it's a non-commercial build by an unambitious hobby builder. But if it's a commercial product and typical of what the merchant sells (anybody can make mistakes of course),  it would definitely be a brand I would have warned people against buying from.

[Jaauuwn]

Thanks Mollymews and ChinRey.  Those are very helpful suggestions and I will check those items out and see what I can find. There are some things I'm already suspect of.

I have a couple groupings of large trees which although each group has a LI of only 10 their display weight is 25110 (20.0 Download / 18.4 Physics / 5.0 Server). The leaves are static however. In general I think I may need to go through a trial and error process deleting the things I think are suspect and also the least attached to. I really like those trees as they set the scene and they hold up without crumpling into triangles every time I change views. Hopefully I will find enough other lag causing items to delete instead.

Thanks again.

[ChinRey]

3 minutes ago, Jaauuwn said:

I have a couple groupings of large trees which although each group has a LI of only 10 their display weight is 25110 (20.0 Download / 18.4 Physics / 5.0 Server).

Those are old sculpt trees and if you have a lot if them, you're likely to get lag issues. Each of the tree groups are made from 10 sculpts - that's 20480 triangles. Judging by the display weights they may be quite heavily textured too and, of course, with plants as old as that they will have alpha blending, not masking.

You shold be able to cut down the lag considerably by replacing them with modern mesh trees with alpha masking but if you do, make sure you choose some with good LoD, that is trees that look good at anydistance, not jsut close up. Big trees deserve to be seen from far away.