Pathfinding: llVolumeDetect(TRUE) and Land Impact changes

There are a couple of changes in the works relating to the forthcoming arrival of Pathfinding in Second Life.

llVolumeDetect(TRUE) Exploit

In the first, the use of llVolumeDetect(TRUE) to create partially phantom linksets will no longer work. Always something of a system exploit / hack, this approach has nevertheless seen widespread use across SL in buildings and vehicles. So much so that when it was discovered that the hack no longer worked in the Pathfainding test regions, it was initially reported on the JIRA as a Pathfinding bug (Pathbug-69).

However, as Falcon Linden points out in the “bugs” JIRA:

Thanks for your interest and passionate comments. First, let me address one of the root issues here: reliance on undocumented behavior that is known to be a bug. I realize that there are many cases of this in SL. I also realize that all of us, as game developers either in RL or SL, will do whatever it takes to implement a feature we want, even if that means exploiting known bugs or idiosyncrasies. The problem is that continued development of a platform (e.g., SL) often precludes backwards compatibility, particularly when systems have exploited “micro details” of the platform. 

Which is not to say Linden Lab is unsympathetic to the issue. Far from it; as in the same statement Falcon goes on to explain:

All of that being said, we as SL developers continue to try to preserve backward compatibility where we can. In this case, I have been able to find a compromise between new features and existing content. Here’s how it will work:

1) If a linkset uses the hack and also uses new accounting (aka mesh accounting or land impact), the first time it is rezzed on a pathfinding sim the hacked prim will be set to physics shape type none. Since the linkset already uses new accounting, this will not negatively impact land impact (in fact, it might reduce your land impact). It may affect a small amount of content that relies on link number of higher numbered prims in collision events by way of llDetectedLinkNumber()

2) If a linkset uses the hack and does NOT use new accounting, the relevant prims will be modified such that they collide only with the terrain. Other than that, behavior should be unchanged. This may impact some land vehicles that previously had hacked phantom prims which did not collide with the terrain.

3) No new linksets can be created that use the hack, and any linking or unlinking event (other than seating an avatar) will remove the hack on existing content.

This should address most of the concerns here. In the future, to create content where only some prims are involved in physics collisions, you will have to use the physics shape type feature.

Ergo, while the arrival of Pathfinding will herald a closure of the llVolumeDetect(TRUE) exploit / hack, LL are attempting to ensure that the impact of the closure in terms of content breakage will be minimal – if it is noticed at all.

Changes to Land Impact Calculations

Coupled to the above change is the announcement that Linden Lab is looking into changing how Land Impact is calculated as a part of the overall Pathfinding roll-out. Nalates Urriah was the first to break the news on the proposal, which  will bring a greater degree of granularity to Land Impact increases.

Under the current system, adding scripts to linksets can result in a sudden (and sometimes dramatic) leap in the Land Impact value. With the proposed changes, this will no longer be the case, with changes resulting from the use of scripts being more gradual. Speaking at the Simulator User Group meeting attended by Nalates, Falcon Linden explains the proposed changes thus:

[17:00] Falcon Linden: Changes to Land Impact that you’ll actually like for a change!
[17:01] Falcon Linden: We’re changing streaming cost for prims to be capped at 1.0 and we’re changing server weight to be: 0.5 * num_prims + (0.25 * num_scripts) but capped at num_prims
[17:01] Falcon Linden: so instead of going from half prim count to prim count by adding one script, it will be a more gradual change to encourage fewer scripts
[17:01] Falcon Linden: right now it’s not capped 
[17:03] Falcon Linden: okay
[17:03] Falcon Linden: here we go
[17:03] Falcon Linden: I have here a linkset of three distorted torii
[17:03] Falcon Linden: The two child prims are shape type NONE and the root is convex hull
[17:04] Falcon Linden: under the current scheme, its download weight is 13.7, its physics weight is 1.6 and its server weight is 1.5
[17:04] Falcon Linden: total LI 14
[17:04] Falcon Linden: under the new scheme, download weight will be 3, the other weights will be the same in this case, and the overall LI will be 3
[17:05] Falcon Linden: if I add one script to it now, the server weight will go from 1.5 to 3.
[17:05] Falcon Linden: In the new scheme it will go from 1.5 to 1.75.

It should be noted that the latter change is still very much a proposal, although it does appear that it is more than likely to go ahead, given it is beneficial to both Pathfinding and the platform as a whole.

With thanks to Innula Zenovka.

Images from Fantasy Faire 8: Siren’s Secret

Important Note: due to the service outage on Thursday 26th April, Fantasy Faire has been extended by one day

Siren’s Secret is the second build at this year’s Fantasy Faire by Elicio Ember, the other being Nu Orne. It takes us from the deep jungle to the wide sea, and a design that, like The Tides, has Atlantean echoes. But whereas The Tides is suggestive of an Atlantis of legend, Siren’s Secret takes a more alien / science-fiction turn; indeed, anyone who has seen the TV series Stargate:Atlantis may well feel a certain familiarity when looking on the style of architecture here. Again the echoes are faint, but they are there, and walking along the flood walkways I would not have been surprised if I’d come across a Stargate and DHD sitting in a corner…

Which is not to say this build isn’t in any way original; as I said, the echoes are faint. In fact, I have to admit that it is perhaps the build that draws me most strongly. This is in part because it does mix fantasy and science-fiction so well, but also because of the manner in which the build extends below, as well as above, the waves, encouraging those who visit to explore what lies beneath as well as being tempted by the creations on offer.

The sim is sponsored by Booshies, housed in an imposing store directly opposite the main teleport area, on the other side of which site the Jail and Bail cell. Around the sim, under the sweeping gaze of the crystal-powered lighthouse (which Elicio has donated to the Faire’s Silent Auction alongside the lighthouse from Nu Orne), you will find stores with a distinctly aquatic feel: Bibi’s coral reef shop, Mermaid Treasure & Boutique, Pacific Sunrise, Mer-chandise Cove and more besides.

Booshies themselves are a new range of breedable about to be launched in Second Life and are the subject of an interview with their creator, Booshie Resident, on the Fantasy Faire website. The website also carries an interview with Elicio Ember, in which he discusses both Siren’s Secret and Nu Orne.

One of the things I like about Siren’s Secret is that it naturally lends itself to being photographed at night – so I make no apologies for the number of night shots that follow…

Siren’s Secret
Your cell awaits: Jail and Bail
The lighthouse and sim by night
Detail above the water
…and below

Dolphin One for the machinimatographers

dolphin-logoLance Corrimal is keeping up a rapid series of releases to his Dolphin Viewer, averaging around one release a week of late. Most have contained nips and tucks or have been driven by SL requirements such as Direct Delivery. However, at the beginning of March he rolled out the “Fujiyama edition” (version, aimed specifically at SL photographers.

With his latest release,, issued on Saturday April 28th and code-named “Fellini”, Lance adds functionality to his Viewer that is specifically aimed at machinimatographers – the code-name clearly being a reference to the late Italian film director Federico Fellini

The functionality in question comes in the form of an adaptation of  Marx Catteneo’s machinima floater. In this the release is somewhat serendipitous for me, as I also linked to one of Marx Catteno’s marvellous videos on the 28th to highlight the architecture of this year’s Fantasy Faire.

In integrating the floater into Dolphin, Lance has modified it slightly so that information is tabbed for easier reference, especially when used on smaller screens, and while it may be aimed at the machinimatographer, it contains a lot of options that SL photographers are liable to find very useful.

The floater can be accessed in one of two ways:

  • via WORLD->MACHINIMA TOOLS in the menus
  • via a dedicated toolbar button called MACHINIMA TOOLS, which has a nice little movie camera icon (note that the button is not active by default, but must be dragged out of the Button Toolbox).
Using either option opens a compact panel, sized to display on laptop screen as well as larger monitors.
Machinima Toolbox with Graphic tab open

The toolbox essentially provides fast, single-point-of-access to a range of Preferences options as well as to a number of other panels and functions, allowing the machinimatographer / photographer to quickly and easily carry out a range of tasks such as enabling Windlight presets for the sky and / or water, adjusting their camera / flycam, enabling / disabling lighting and shadows, adding / adjusting depth-of-field, adjusting shadow and occlusion settings and much more besides.

Each of the tabs in the label is clearly laid out, and some benefit from having certain functions disabled (grayed out) until such time as their controlling option is enabled. In the Graphics tab, for example, the drop-down for selecting the required lighting types (None, Sun/Moon, Sun/Moon+Projectors), is disabled until the LIGHTING AND SHADOWS option is checked.

Rather than waste words describing each of the tab, here is a set of screen captures for the remaining tabs in the floater:

Camera settings
Shadows & Occlusion
Depth of Field
“Miscellaneous” – currently derendering options

The derendering options are liable to prove useful for eliminating bystander avatars who are having a detrimental impact on camera movements, etc., when trying to shoot a video, while the “Miscellaneous” tab as a whole leaves room for further options to be added, should they be required / possibly requested.

Other Updates

As well as the machinima options, the blog post for the release notes the following updates are also included:

  • Getting a worn attachment into edit by right-clicking it in your inventory and selecting “Edit”-
  • Opening a Landmark on the map from your inventory, similar to what you can do from within the Places window.


I’ve not been able to thoroughly test the release in my usual manner due to time constraints elsewhere. However, in the tests I did perform, using my home sim as usual (3 others present in the sim) and both PC and Viewer set to my usual defaults (see the panel on the right of this blog’s home page), I found this release of Dolphin performed as well as other recent Viewer releases from the majority of 3.2-based TPVs. Running with deferred rendering off (no shadows / lighting enabled), the Viewer comfortably ran with an FPS in the mid-30s at 390m, with this increasing to the low 50s at altitude on my build platform (2850m). At ground level, the rate dropped very slightly to average at around 30-21 FPS.

Enabling deferred rendering and setting the lighting option to Sun/Moon+Projectors saw my frame rates fall to around 19-21 FPS at 390m, and to the mid-teens when at ground level. This was again pretty much in keeping with recent releases from the likes of SL and Firestorm.

Overall, an interesting new addition to Dolphin which should prove to be of interest to those interested in both video and photography.

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