How to measure distance in SL

I need to setup security on some land and the orb only protects 96m. The land is considerably larger than that, so I need to figure out how many orbs I need. How is distance measured in SL from an avator's point of view?

The X-Y-Z Coordinates on your map are done in meters, as well as all prim measurements. The numbers you see displayed are an SL meter. (^_^)

There is a big debate over how this meter relates to an avatar in scale... But, you're talking about a security sensor, so rely on the map coordinates and prim build size while considering space in SL meters. (^_^)

Another thing I did myself is find a program that will draw in measured scale and lay out my plot in 4Mx4M squares to get an idea of its exact form. Like this... I used Visio. (^_^)

If you look at the top of the screen you will see coordinates.

You can go to the edges of the parcel and subtract the appropriate coordinates to find the size of the parcel.

You could find a 96 meter radius megaprim sphere and use it to measure with.

Remember that any sensor range is a sphere, as well. And that 96 M is the radius of the sphere, not its diameter. It isn't a square volume of space.

I usually map out the parcel as a 4M grid, and position 96 M radius circles over it to cover the area, planning on the orbs being at the same height as most of the planned activity. That gives you maximum coverage. 5 orbs can cover a whole sim with a 96M range. You overlap them, positioned like the pips on the 5 side of a 6-sided die. The center one is the master control, set to just reach to the other 4 within its limits. Technically 4 can cover a sim, but if they require a central controller, to communicate back to all the orbs, then a 5th one at the middle can listen to and send messages to all the others. 4 by themselves will always have one in each corner that the other 3 can't directly hear or talk to.

Just a note to be aware of the fact that a security orb's reach *is*, as previously mentioned, spherical, and to keep the outer edge of that sphere within the parcel's boundary and be considerate of neighbours, even if it means the corners of your parcel are unprotected.

A neighbour of ours set a security orb up a couple of months ago, and although the corners of his plot were protected, that meant the edges of the security sphere intruded 10m across the parcel border and into our house, rendering one third of our home unusable due to constant ejections. He was unaware of this (although the situation was resolved quickly when we contacted him) so if you have neighbours nearby, please be aware of this

That doesn't always happen because any halfway decent security device only deals with people who are on or above the land, even though the scan picks up other people as well. That's why such devices need to be owned by the landowner - often deeded to a group for that reason. But it can happen when the land is rented from the same person/group that owns the adjacent parcel(s), as is common on private islands.

So, if the parcel is owned by someone other than the owners of the parcels around it, the range can be set to the full 96m.

Visio!! I've spent the last week trying to remember that name. Thanks.

ya mine when i used to use them was set to only work within my land perimeter but could sense the full 96 meters..like Phil said..that was owning my land..not sure if it works the same for rentals..you could just set it for your house and lower the range if you had to .

I suppose if you put a texture of a parcel on a prim at a known scale you can use llDetectedTouchUV to make measurements. Include a prim of known size in the image to determine the scale.

Correct, but whoever configures the orb has to know this, so Skell's point was a good one. It should be the default, but wasn't in two excellent popular orbs, the last time I checked.

I suggest that rather than protecting the whole sim (which you can't do anyway), you protect specific sites or buildings. This will be far less laggy. In any case, be sure not to scan too frequently. There's rarely a need to scan more than every 10 seconds, and frankly, 30 should be reasonable. Exceptions are things like military targets, where the whole raid would be over in 30 seconds. But if it's just to keep the riff-raff out so your toys don't get used while you're gone, no need for frequent scans, and no need for fast response times (give people at least 30 seconds to vacate, for goodness sake).

You can get a good idea of coverage using a phantom, mostly clear 182M diameter sphere. However, prims like this can be difficult to manage if you're not a fairly experienced builder, so consider having a friend help.

192

/me can't add!

I generally just wing it

"Security" devices are by definition indecent.

I haven't ever had use for a security orb, but it seems to me the best way to avoid scanning over parcel boundaries (the "spherical scan vs. rectangular plots" problem) is to mount sensors on the corners and have them them point inward with a sweep of PI/4. Do any of the security orbs have configurable sensor angles like that?

That not only requires more orbs, it also makes it more difficult to be sure you've covered the entire interior, plus you need to handle duplicate detections. It's simpler to just scan a larger area and check the parcel.

hippoSECURE. copyable, and can be networked with other units to share access lists. And can define cubic (rectangular) spaces.

Maybe sensors should be made to be scan a box shaped volume instead of a sphere or part sphere.

Or make a scan area interface similar to the parcel subdivision interface.

llOverMyLand() is a great tool to refine a sensor sweep, but it seems most of the shit orbs peoples use do not do the check...

If I want precise measurements I just make some bars from the cube building block. I have 10 metre, 20 metre, 30 metre and 40 metre bars.

I made and sell one that *only* uses llOverMyLand() and can't be used in any other way. But there was a bug where people in neighbouring sims, who were within the scan range but on land of different owners, were also returned as though they were on or over the land. I had to use a workaround for it because devices placed near sim borders picked up wrong people. Those people received the warnings but they couldn't be removed, of course. I don't know if the bug still exists, but the workaround in mine still exists.

I've been asked to make one that works on any land, but I've refused to do it because it could be used badly.

It's easy to criticize when you don't grasp the complexity. There are so many different situations in which security devices are used, and people all too frequently don't pay sufficient attention when they're setting them up.

The most common case where this happens is when the land is group owned but the security orb is owned by one of the group members. In that case, you can't use the my-land check. It's best to avoid that case, but there are times when it's appropriate.

Deed the orb to the group. If you can't do that, then don't set up a security orb at all. It's not like there are all that many cases where even HAVING one is appropriate that this would be a huge restriction.

Hipposecure also restricts to parcel with a -p flag so no worries about neighbours...