Sim Crossings

Someone posted: [snip] it is one of my favourite spectator sports to sit under my tree watching vehicles roar along then disappear underground in a hail of expletives.

Reading that triggered something in the tiny brain of mine - am I interpreting this correctly that the occasional walks I take underground and where I can't get turned back around, are actually sim crossings?

Well, quite often, not always though. Watch the position indicator at the top of your screen. If any of the co-ordinates go below 0 or over 256 then you are having an issue crossing a sim boundary.

1) Sometimes you just start going underground because your connection has become faulty (does not have to occur at Sim crossing);
2) Some builds include an underground section for people to walk in;
3) The Linden built great wall of Linden that crosses many sims is very laggy and it is very easy to start walking on the top layer and end up sinking . . .and sinking and end up inside the inner tunnel (if you find yourself in this seemingly unescapable tunnel, fly to the highest point you can reach, go towards the edge, move your camera upwards and find the ledge, "sit" on the ledge. now stand up - you are now on the outer topmost layer);
4) I have forgotten the question, sorry.

That is a badly designed road. Most likely one that has prims that just butt up against each other from each side of the sim boundry. The problem can be virtually eliminated if the road builder includes one extra prim on each side, attached to the prims on one side and then pushed through to the other side, forming an extension of the road from either side. This gives the SL client data on where the surface is SUPPOSED to be as they leave the sim, and before the new sim tells them where it is on that side.

When crossing a sim boundry where there is no road, the problem is that the sim you are leaving doesn't know where the ground is in the next sim, and the sm you are entering hasn't told your client yet, for certain, where the ground is. So you sink...

so THAT is what that was!

i took my motorcycle out for a spin the other day and raced across the top of the "wall" thinking it was a continuation of the road that led up to it.

tho i didn't find it laggy in the least.

There is a dealership adjacent to the great wall that allows rezzing vehicles. So I go there to rez vehicles. Unfortunately, it is very laggy there.

That is a very neat thing to see though The great wall.

Ceera Murakami,

I just want to say that is an Excellent example and Im going to have to do a linking road like you said for sim crossing when we extend our sim.

Thank you
-Cherry Hotaling

This is an awesome answer! I've never been able to figure out why this happens. Does this explain the same phenomenon when you fly across sim boundaries in an airplane? I've done that at, say 300 meters and all of a sudden I'm underwater for a sec, then back at 300m. The old sim doesn't communicate well with the new one and there's a delay where it sorts out where my plane is supposed to be.

Ah ha! I feel like I've learned something today.

Thank you. Yes, I believe the delay in getting information from the new server as you leave the old one is the reason for most sim crossing glitches.

If you would like to see an example of a sim-crossing span like I was describing, go to the Sunrise Hopes sim. There is a 250 M long green drawbridge leading from that sim to the Amarin Bei sim. I built it in the way I am describing above. As I recall, the sim edge is two arches North of the draw span. Look at the cross-over point with Highlight Transparent on, and you'll see the two extra prims.

The trick to making this is to link the extra prim while it is still in sim "A", with the rest of the linkset, and then edit selected to push just that one prim into place in sim "B". You can't link a prim in one sim to prims in another sim, but you CAN push them across the line. The part that extends into the sim is treated as phantom by the sim the linkset is not in. But the extension gives your old server enough information to keep you on the right plane until the new sim takes over your movement vector.

"The right plane"? Don't confuse Trout


I've noticed the invisible pairs of overlapping invisible prims at sim boundaries on Linden constructed roads. They are described as "Linden Road Buffer". They certainly help at slow speed.

In my motorbiking along the roads I slow down at sim crossings. Otherwise we can run out of buffer before the sim handover completes.

I had understood that every sim recorded the details of the surrounding sims for a distance of 10m in from the boundary. Presumably that was intended to achieve the same effect, provided the centres of primsets beside boundaries are with 10m if the boundaries.

Sailors have a lot of trouble with sim crossings, especially if you are travelling at a good speed.

What we do is hold off from any keyboard use at sim crossings, no chat, no sail changes or anything. Keep hands off the keyboard (and the mouse!), and the transition will be a lot easier.

Property lines, and mini map are your friends as well.

Of course all of us end up eating gravel at some point, but if you have 4 boats crossing a sim line at one time it can get a little hairy!

If you go to sailing areas, you will see a lot of buoys delineating the sim border so sailors will know to be careful.

What we need in SL is a standard Special Mark for sim borders. Perhaps a phantom strip just under water level would be good?
Property lines are a difficult guideline as they can be a good distance underwater, and hard to judge from an angle.

Cardinal Marks, Channel Marks and Isolated Dangers don't give the appropriate message.

I have a little place in a sim that borders a Linden protected snow sim, and I thought I was being all brilliant by doing this linkset bit to extend my skybox house into it, until I fell through the floor and crashed to the ground when I hit the sim boundary. I didn't realize then that my extension would be phantom! Ah well, at least I have a great view, and I don't really need to build out when I can build up.

The sim crossing was very smooth, though.

Building on that into the generality: (and feeling dirty for drifting)

If someone has View / Property Lines selected, how about the client rendering property lines a metre or so underneath eye-level in addition to the normal lines on the ground?

That would would be good for:
1. Slowing at sim boundaries, whether boating or flying
2. Flying/sailing along Linden protected roads/canals where the normal ground level property lines are too far below to judge properly
3. Building in the air
4. Avoiding buying a plot plus build where the build accidentally encroaches on a neighbouring plot
5. Avoiding buying a plot plus build, where the seller has a 16m 'ransom' plot hidden in the middle of the plot under the build.



Worth a JIRA??

Does anyone else crash just for fun or is it just me? Its just me isn't it. oh well...

I know a place where I can get a good speed going on the water in a boat or surf board or my dentist chair, then as i cross the border, it must og into a no build zone or something because my vehicle disappears and I am sent hurling forward through the sea lol.
It can be so much fun, I do this sometimes if I want a laugh

it's a linden road heehee!

(it was me that Honeybear originally quoted)