Question Regarding llCastRay Limitations

[Charliedru Lannock]

I am curious about CastRay limitations before venturing into a commercial project.

I have researched the Jira SCR-199 (https://jira.secondlife.com/browse/SCR-199) regarding reduction/removal of llCastRay limitations.

 

However, the last that was posted by Falcon Linden on 26/May/12 was the following:

"The resource pool limits have been disabled on pathfinding regions and will be removed gridwide when pathfinding is released. The 'region performance too low' has not been change. Note that that you should still check for all error codes as the limits may be reapplied if we discover performance problems, though I no longer expect that to happen."

 

Pathfinding has not yet been released grid-wide, so I believe the pool limits are currently active on the main grid. If they are disabled upon release of pathfinding, then it may be possible they are activated again in the future. Venturing into a major commercial project would be difficult without some further understanding of the current limitations and possibly long term limitations...

 

So finally to my question:

 

I plan on having anywhere between 50-200 objects on a private sim casting rays upon a user's click. On click, each object will cast anywhere from 1 to 5 rays. User might click multiple times, causing more rays to be casted by the object.

Performance must be real-time, therefore I cannot sleep the script in any measure above a fraction of a second.

Rays would be filtered to detect other prims whether scripted or non-scripted. Not agents, not land.

On top of ray casting on click, objects will cast rays on their own in the same range of 1-5 casts, but not at regular intervals. It could take 3-7 seconds before auto rays are cast for each individual object.

I am curious exactly as to how fast llCastRay replenished its pool. The wiki states a frame, but I am unfamiliar with a time value with respect to a frame. Would 200-1000 rays every 2-3 seconds be too much for the current and/or possible future limitations of llCastRay?

 

Any help would be appreciated, thanks.

CDru

[Rolig Loon]

I really don't know the answer to your question, but your basic premise is flawed.  Pathfinding was released grid-wide a long time ago.  Most private sims do not have dynamic pathfinding switched on because most private sim owners have no use for it, but they could activate it any time they wanted to.

BTW, it's no longer possible to do a decent search of the JIRA.  Linden Lab removed that option last summer, so the only JIRAs we can see are ones that were posted before then.

[Charliedru Lannock]

Hmm, interesting. From what I understood, it was still in Beta with an opt-in program for private sim owners on the main grid to allow pathfinding in their region to assist with the testing prior to launch.

 

As per Server Release Notes on RC BlueSteel, RC Magnum, and RC LeTigre, they are still performing updates on pathfinding and installing new features (Last was on 2013-06-19).

http://wiki.secondlife.com/wiki/Release_Notes/Second_Life_RC_BlueSteel/13

 

 

My focus on pathfinding not being released was only regarding the restrictions of CastRay which were announced by Falcon Linden to be disabled when pathfinding is released. By released, I wasn't sure if it was meant Grid-Wide release, or this Opt-In Program for some region owners, which isn't actually an official launching from my understanding, or I'd be able to use it commercially, grid-wide.

 

My main worry is the llCastRay limitations, but thanks for bringing this to my attention, Rolig. It is possible that the llCastRay limits were disabled when pathfinding was released in this Beta phase (as the post was dated back May, 2012).

 

I'm still interested if anyone has any experience with limits on high volume of cast rays in short periods of time. Would be of great help and it'd save me a lot of trial and error time testing it out. Wouldn't want to have any scripts break down someday during an event with people present, lol. ^^

[Jenny Siddeley]

I'm not sure as I haven't been playing with llCastRay much, but I think the answer to your question might also depend on the length of the rays and the number of possible hits for each ray. The shorter and smaller these values are, the more you can have I guess.

[LepreKhaun]

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Charliedru Lannock wrote:

...

I am curious exactly as to how fast llCastRay replenished its pool. The wiki states a frame, but I am unfamiliar with a time value with respect to a frame. Would 200-1000 rays every 2-3 seconds be too much for the current and/or possible future limitations of llCastRay?

 

Any help would be appreciated, thanks.

CDru

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A "frame" in this context* is referencing how the sim server updates the sim. A frame happens, ideally, 45 times each second though it tends to vary a small amount each second. Each frame entails a LOT of activity which is done in frame subdivisions referred to as "slices", which are allocated to all active elements (avatars in the region, active tasks, falling objects etc).

So, 2-3 seconds would be 90-135  server frames and 200-1000 rays equates to app. 2-8 rays being attempted by your task during each slice of its processing time. Whether that is too much or reasonable would have to be determined by you for your specific case.

 

* The viewer also has its own "frame rate", which is dependent on many factors outside of SL, including the internet connection at the time, video card and processing power of the client's computer, and (possibly) the sun position in Delhi at the moment.

.

[Charliedru Lannock]

This is excellent information and exactly what I needed! Thank you very much, LepreKhaun!

[Madelaine McMasters]

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LepreKhaun wrote:

* The viewer also has its own "frame rate", which is dependent on many factors outside of SL, including the internet connection at the time, video card and processing power of the client's computer, and (possibly) the sun position in Delhi at the moment.

---

I have been carefully watching my SL frame rate and I think I can narrow the "India effect" you've described, LepreKhaun.

While the Sun position in Delhi probably does have some influence, it changes both slowly and predictably. I've noticed that that my frame rate drops precipitously every time a miracle is performed in the name of the great Guru Raghavendra Theertha. This correlation isn't sufficient to allow me to theorize that it's actually my iMac providing the motive power for the miracles, but I'm sure someone else will draw that conclusion.

I've also noticed that my RL neighbor walks over to visit every time I try to slip into SL. It's a mysterious world we live in, LepreKhaun... be careful.

ETA: If you listen to Guru Raghavendra's mantra long enough, low frame rate will be the least of your aggravations.