prim count glitch? / land impact

[mobiusonemasterchief Infin]

i just completed a small build and its all strait prim with no special mods on it and SL says its 253 Land impact!?

 

actual prim count is 65 prims.

whats going on ?

 

 

[Perrie Juran]

Please use something other than drop box to post pictures.  It requires an account to view.

On the top of your message window between the chain link and the film strip is a little tree icon.

That allows you to add pictures here.

ETA:  Thank you for fixing! 

[mobiusonemasterchief Infin]

ADDUM---

as soon as i unlinked the 3 prim straps the prim count becomes normal , the straps are strait prim too nothing special,

then when i link the straps on the count goes crazy,

the straps are only 3 cylinders hollowed and pathcut with a texture added.

by themselves , linked together 3 prim, when linked to the rest of the build, the count of LI and prim count goes crazy .

 

[Lexbot Sinister]

Did you put materials on it? Specular textures, normal maps, etc? Check the texture tab.

In that case, it's not a glitch but the new LI accounting, that reflects the real physics impact of the build on the sim.

If you want to keep materials, but get a "normal" prim LI, go look for toruses and other twisted prims and set their physics shape to none. You can do that to all prims except the root. They will be walk-through, but get lower LI.

 

 added:

The Li will shoot up if there are materials anywhere on the linked build, and you link turtured prims to it. Set the physics shape of the prims to none.

[mobiusonemasterchief Infin]

textures will alter the LI of  a build ? ...........

 

did a test and set the build to all default *prim/wood texture. this did not alter the LI count.

how can adding 3 cylinders to a build drastically change the count ?

further, NOT pathcutting and hollowing the 3 prims -- no change.

path cutting and hollowing the 3 cylinders makes the LI go nuts.

 

[Amethyst Jetaime]

Did you set you prims physics to convex hull?

 

[Lexbot Sinister]

---

mobiusonemasterchief Infinity wrote:

textures will alter the LI of  a build ? ...........

---

Yes, but not any textures, not the diffuse map. The specular map and the normal map will.

You are very much welcome to rant at LL for this if you like- I have been, frequently, since materials came out. Apparently it works as intended. That it confuses the heck out of even a seasoned builder, is dismissed.

So i'm just saying what to look out for, then LI rises.

[Perrie Juran]

"Legacy prim objects have a land impact rating equal to the number of prims they contain.  However, any object's land impact is calculated using download, server, and physics weights if it meets any of the following conditions:

• The object is an uploaded mesh.
• The object is linked to an uploaded mesh.
• The object, or any part of the object, has a physics shape type other than Prim.  You can change this on the Features tab of the Build Tools window.
• The object has a normal or specular map applied to it."

 

http://community.secondlife.com/t5/English-Knowledge-Base/Calculating-land-impact/ta-p/974163

[arton Rotaru]

All that plus using an alpha mode other than blending.

[Rolig Loon]

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mobiusonemasterchief Infinity wrote:

[ ... ]

how can adding 3 cylinders to a build drastically change the count ?

further, NOT pathcutting and hollowing the 3 prims -- no change.

path cutting and hollowing the 3 cylinders makes the LI go nuts.

 

---

Yup.  There's your problem.  Simple prims have a minimal effect on L.I., but if you start cutting, hollowing, twisting, slicing, or otherwise torturing prims, the L.I. will usually increase dramatically because the servers are now having to do significantly more caculation to keep track of their physics shapes.  The same is true for some other commonly-used but non-simple prims, like the torus, even if you don't modify them. 

[Chic Aeon]

Rolig is on the money. I had that fun phenomina last eve. I had a simple building made with hollowed cubes and one path cut, some regular cubes. It was 12 prims (LI). I wanted to save some LI and it didn't matter if it could be entered as was just for show, so switched to Convex Hull and got 5. THEN I decided to turn it back to prim and it was a whopping 57!

On the plus side sometimes you get some GREAT bonuses linking mesh to prims or very simple mesh to mesh. Not quite  a mystery but still I get surprised. Any time you "torture" a prim the server has a lot more difficulty rendering it. Hence the cost. You might try turning the whole build into Prim-O-Mesh (third party viewers).

 

Right click on object > Save As > Collada (using Firestorm - different path in different viewers). Then upload a mesh and see if that solves your problem.  You can test on the beta grid or just try the uploader and see what it is going to charge you for LI.

 

 

[Kwakkelde Kwak]

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Chic Aeon wrote:

Rolig is on the money

. I had that fun phenomina last eve. I had a simple building made with hollowed cubes and one path cut, some regular cubes. It was 12 prims (LI). I wanted to save some LI and it didn't matter if it could be entered as was just for show, so switched to Convex Hull and got 5. THEN I decided to turn it back to prim and it

was a whopping 57!

On the plus side sometimes you get some GREAT bonuses linking mesh to prims or very simple mesh to mesh. Not quite  a mystery but still I get surprised.

Any time you "torture" a prim the server has a lot more difficulty rendering it

. Hence the cost. You might try turning the whole build into Prim-O-Mesh (third party viewers).

---

Rolig WAS on the money. So I'd like to emphasise that it's usually the physics shape causing the drastic increase in LI. Rendering isn't directly taken into the LI calculation at all. Download weight, which is often closely related to render load is however. Torturing a prim can change the basic shape, making a box hollow makes the amount of triangles rise from 108 to 270. However, applying a very small taper will decrease the amount from 108 to 12. (And a hollow box with a taper has 42 triangles). Other modifiers will not change the basic shape at all. All in all the chances of the download weight getting higher when a prim is tortured are high, but the effect won't be as drastic as the change in physics weight.

To illustrate, a box which is hollowed and twisted from -180 to 180 degrees:

A normal (0.5x0.5x0.5) box has a physics weight of 0.1 and a download weight of 0.1 (and 108 triangles)

The tortured box has a physics weight of 90.4 and a download weight of 1.0 (and 1898 triangles)

So the download weight (calculated as mesh) of the tortured prim has risen by a whopping factor 10, but the physics weight by a mindboggling 904.