[Opensim-dev] Region Crossing State

Diva Canto diva at metaverseink.com
Mon Jun 16 16:25:50 UTC 2014


I'm sure vehicle border crossings are important for some situations.

For me, they got a lot less important now that OpenSim supports 
variable-sized regions. There are also alternatives (co-simulation) to 
moving vehicles along very large areas that are able to avoid crossing 
borders altogether, therefore avoiding the "bumps" on borders and the 
extra load that moving vehicles and crossing borders entail. These 2 
things (varregions and co-simulation) don't exist in SL, but they're 
superior in some respects, because they avoid crossing borders 
altogether; it's much smoother, keeps the load down, and avoids running 
into security issues.

Here's a video showing a large-scale traffic co-simulation:
https://www.youtube.com/watch?v=291yE_9eefU#t=4m02s
Co-simulation means that one simulator has part of the objects, in this 
case the vehicles, and the other simulators have the rest of the scene 
objects. The vehicles never cross borders, even though they move along 
very large distances (in this case, 3km x 1.5km).
I talked about how to do this at OSCC'13.

This is not to say that I don't support adding proper vehicle border 
crossing support to OpenSim, if someone cares to do it. +1!
But I would never trade the borderless way of moving vehicles for the 
SL's way of moving vehicles, so vehicle border crossings has been very 
low priority for me, personally. One of the perks of reimplementing the 
server-side is that we can do things that can't be done in SL!



On 6/16/2014 7:10 AM, Frank Nichols wrote:
> I guess no one cares about region border crossings ...
>
>
>
> On Sun, Jun 15, 2014 at 9:42 AM, Frank Nichols 
> <j.frank.nichols at gmail.com <mailto:j.frank.nichols at gmail.com>> wrote:
>
>     Maybe someone can answer this - I am aware of NPVs but have never
>     used them. I am pretty sure than as of a year ago you could not be
>     seated and do a region border crossing, however a lot of work has
>     gone into OS in that area in the past 6 months and it may be
>     possible now.
>
>     Frank
>
>
>     On Sun, Jun 15, 2014 at 1:22 AM, Mike Higgins <mike at kayaker.net
>     <mailto:mike at kayaker.net>> wrote:
>
>         All very good questions, but there is a fundamental assumption
>         that all vehicles are physical.
>         1. Can non-physical vehicles (NPVs) cross sim borders?
>             An NPV is a non physical object that uses llSetPos,
>         llSetPrimParams,
>         llSetLinkPrimParamsFast(LINK_THIS,[PRIM_POSITION....]) or
>         llSetKeyframedMotion to move across a SIM boundary.
>             On some grids, NPVs cross SIM borders just like physical
>         vehicles.
>         2. Can NPVs cross SIM borders with an avatar sitting on them?
>         3. Can NPVs cross SIM borders WITHOUT an avatar sitting on
>         them? (for example a ferryboat that makes regular runs from
>         one SIM to another, and keeps making the rounds even when empty).
>
>
>         On 6/13/14 10:58 PM, Frank Nichols wrote:
>
>             OS is now 7 years old and the fundamental feature of
>             crossing from one region to another while riding on or in
>             a physical vehicle is not working. I, and most of the
>             community, are aware that there are partial
>             implementations being worked on, and at least one grid has
>             an implementation similar in functionality to SL - but
>             that implementation is not yet available to the OpenSim
>             community in general.
>
>             Obviously, if it were easy to implement it would be done -
>             it may well be impossible to implement...
>
>             PVC below stands for physical vehicle crossings between
>             regions with avatar(s) riding the vehicle(s).
>
>             1. Is PVC a desirable feature - does the OpenSim community
>             want to be able to ride physical vehicles while crossing
>             region borders? With the implementation of var-regions,
>             crossings are less of a necessary feature - however, a
>             smooth or bump-less crossing combined with variable sized
>             regions would give grid designers a lot of flexibility.
>
>             2. What features would be expected of a solution?
>
>             a. Bump-less region crossings - ie. unlike SL or other
>             implementations, bump-less region crossings would be a
>             desirable feature. I would prefer that region crossings be
>             bump-less - this means to me that there is no movement
>             shuddering visible while crossing, all scripts transfer
>             their running state smoothly, and sounds would continue to
>             play smoothly. A person observing their avatar cross from
>             one region to another would not be able to see/detect any
>             sign that a crossing has just taken place except a script
>             reporting which region it is running in would suddenly
>             begin reporting that it is in the destination region.
>
>             b. Should PVC be required to work on all physics engines
>             mainly ODE and BulletSim at this time. My feeling is that
>             I would be happy if PVC only worked on BulletSim. I
>             understand that many people still use/prefer ODE - but if
>             PVC only worked on BulletSim (initially) I would feel that
>             would be a good step, and then if there is a demand from
>             the community and someone available to do the work, it
>             could possibly be ported to ODE.
>
>             c. Would it be necessary to be able to cross between
>             regions running different physics engines? In other words,
>             would the community expect a physical vehicle to be able
>             to cross from a region running ODE into a region running
>             BulletSim?
>
>             d. Would a "bumpy" crossing between regions running
>             different physics engines be acceptable with a smooth
>             crossing only being available if both the starting and
>             destination regions were running BulletSim.
>
>             e. Would Scripts need to cross smoothly between starting
>             and ending regions - or would a script restart/recompile
>             be acceptable? What would be acceptable behavior if the
>             configuration of the destination region is different than
>             the starting region concerning scripts. I expect the
>             scripts to stop running and report an error?
>
>             f. Would a physical vehicle size restriction for PVC be
>             acceptable? What would be the expected result of a "train"
>             (linked set of "train cars" populated with avatars)
>             crossing? Again, I think this should be smooth and
>             bump-less assuming the starting region and destination
>             region meet some criteria.
>
>             g. What would be acceptable behavior if a PVC is attempted
>             between regions with differing physical link set
>             limitations - such as number of prims, size of physical
>             prims, etc. Would the vehicle be denied access to the
>             destination region if it's construction exceeded
>             destination region limits?
>
>             g. What is the expected behavior for PVCs concerning
>             permissions of the vehicle entering and/or leaving
>             regions.For example, would the vehicle flying over a
>             region have the same expectations for access permissions
>             that a avatar flying over a restricted parcel would have?
>
>             h. What would be the expectations around PVCs and
>             HyperGrid? Would the community want/expect a physical
>             vehicle to be able to be ridden to a different grid via
>             hyper grid technology. If so, would it be required to work
>             in any combinations of hosting hardware (linux, windows,
>             osx, etc)?
>
>             i. Should vehicles be able to be ridden while teleporting?
>             Should such teleports be able to teleport within a region
>             as well as between two regions on the same or different grids?
>
>             j. Are there expectations concerning the altitude a PVC
>             can take place? Submarines? Aircraft? Sub-terrain Tunnels?
>
>             k. Obviously we would all like our favorite client to
>             support the PVC, but would humpless HG enabled PVC be
>             acceptable if was initially supported by a single popular
>             client? Obviously the implementation would have to be
>             OpenSource and licensed according to OS requirements, so
>             other clients/viewers would be able to add support at
>             their desecration.
>
>             What other features or capabilities would you like to see?
>             Personally, I would like to see capabilities beyond what
>             SL supports - what about you? Is Sl compatibility a
>             requirement for PVC? OS is 7 years old, I believe it is
>             time to look forward to what the community wants, and not
>             continue to just "keep up with SL". Hyper-grid is an
>             excellent example of OS taking the lead - maybe it is time
>             for PVC to take the lead also.
>
>             Let me be clear I have nothing but admiration for the OS
>             developers. I am not complaining about that they have
>             done. I am amazed at the outstanding work they have done
>             and the feature set they have provided to us. My
>             discussion here, is an attempt to determine if there is a
>             desire for PVC, or if the OS community finds the current
>             state of region crossings to be acceptable.
>
>             Let me also be clear also that I understand the features
>             mentioned above may not even be possible - that is not
>             what I am interested in, I want to know what would the
>             community want a PVC implementation to look like if their
>             dreams could come true.
>
>             Thank you.
>
>             Frank Nichols
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