Tuesday, June 24, 2014

The Case of the Multiplying Prims

Today I bring you a tale of rogue objects, Linden mismanagement of Land Impact calculation, self-multiplying prim linksets, and a promise to soon tell you of a scheme to save a prim here and a prim there that eventually amounts to hundreds or even thousands of free prims.

So, it all began a week or so ago on our Homestead sim Whmsy Kaboom. I was playing with my Descender, removing prims in preparation for repurposing it as a tour vehicle.

We usually keep about 200 of Kaboom's 3750 prim allotment free; this for accommodating vehicles crossing from our other sims and a couple of temp-on-rez robots up at the ever-full-to-capacity Robot Sanatorium.

I had whittled the Descender down from its original 96 to about 40 prims when I got a message saying it had been returned because the parcel was full.

I checked to see if anyone was in the region. No, I was alone. Then I clicked About Land and selected the Objects tab so I could see the prim count-- 198 prims available. So that was good-- but why, then, had the Descender disappeared?

What was to happen would have been a lot easier to figure out if I hadn't been immediately confronted with a new problem. When I tried to rez the Descender on Whimsy, I got a parcel full message. What?

We keep a couple of thousand prims free on Whimsy, and by my estimation I had just freed up 500 or so by replacing high-prim antitque birds and fish with better-looking newer models. My guess was we had 2500 prims to play with-- but About Land told me only 442 prims were available.

Okay, now, this was weird.

I wondered if perhaps there were four or five Descenders somewhere on the land because of my failed attempts to rez it, but I was unable to find them. I even flew to the 0,0,0 sim corner and looked below the mesh of the land. No Descender.

I went to Leaf Shermer's sim Whimcentricity and rezzed the very Descender that had been returned to Lost and Found. To my astonishment, it showed a Land Impact of 688!

I made certain the Physics Shape was set to Prim and not Convex Hull-- it was-- but still it was showing 688 prims.

No wonder it had been returned from Whimsy Kaboom! It had certainly filled the parcel! But why? It had only about 40 prims and Physics Shape Type had been set to Prim when it suddenly disappeared. What was going on?

I called the concierge line and had a productive conversation about land impact. The helpful Linden with whom I spoke suggested I delete the offending Descender and pull out another-- which I did. Afterward I researched land impact and learned something interesting and fortunate, which I'll talk about in the next post.

I was still unable to determine what object or objects might be taking up 2000 prim space / land impact; the handy Advanced Object Scanner search HUD I bought long ago at Conover's gadget wasn't helping. At Sweetie's suggestion I tried Firestorm's Area Search, sorted by Land Impact, and there it was-- our PG Den of Iniquity!

The PGD of I is a modified and slightly stretched airship called the Gilded Gobbler. For several years now it has been functioning as the home for our many Second Life Games.

At 190 prims, it's a fairly land impact-intensive build, but well worth it. But guess what! It was clocking in at 2146 prims! Here's a screen shot showing the Edit window, Note the prim shape is set to Prim, meaning it should have been consuming no more than 200 land impact units instead of the 2146 that is registering.

Here's a screenshot showing the same results in area search.

Here's a screen shot showing 1914 prims free (up from 442 because I had just FREED UP 2000 PRIME WHILE MAINTAINING THE SAME CONTENT, which I'm dying to tell you about!).

Now here's the same window showing 3861 prims free.

What's the difference? The prim count dropped dramatically because I set the Physics Shape Type of the PGD of I to Convex Hull instead of Prim.

The problem is the Physics Shape Type must be set to Prim for the PGD of I to function properly.

Okay-- so now I knew why Whimsy's 2500 or so free prims had suddenly become 442. I felt I was on the brink of discovering what was going on.

After some thinking I realized I had temporarily switched both the Descender and the PGD of I linksets from Prim to Convex Hull. Somehow that had screwed the pooch; when I set them back to Prim the server software became confused and grossly exaggerated their land impact.

This is a dangerous bug, and one Linden Lab must fix immediately. I have submitted a ticket which will hopefully help to make them aware of the problem.

1 comment:

Anonymous said...

Thank you SO much for posting this! I have been trying for a couple days to figure out what happened at my own place. I bet you this is it. As soon as I get back, I will definately check. Thanks again!