Difference between house and ship ?

Hello,

as a newbie, I have another question.

If it is only possible to have 117 prims per 512 m2 of space, how is it possible to make a model of spaceship which is 80x35 m and modelled with 2026 prims ?
Something like the Interloch which is offered at SLEXCHANGE web site.

Does it means that if the creation is not tied to the land, there is no prim limit ?

Oh, if that were true...

Yeah, nagannahappen. Not even close.

Edit: Since you asked how it's possible, it's possible by buying bigger land. About 12,000 m2, give or take.

So, how it is possible to make a ship with more than 2000 prims ?

Buy more land. Lots of land (see above). That's a heck of a lot of prims. You'd need enough area to physically contain it, too.

Or go to a sandbox too, I suppose. Can't leave it there, though, but you CAN rez it out and look cool.

You need to be building on a big enough piece of property that would allow you to have more than 2000 prims out.

I do not want to buy the ship.
I only saw the ad on the slexchange marketplace and I was wondering how it is possible to build and use such thing.
There is not mention in the ad that the owner must own something like 8192 m2 of land.
And even if I will have 8192 m2 of land (and pay taxes in RL $), how is possible to fly with ship ? If I will fly above some houses nad the prims count will suddenly become higher than limit, what will happen ? The ship explode or the houses will disappear ?

Oh, well...that's entirely different. Assuming that the ship is, in fact, flyable (doubtful) it will be a 30-prim physical object you ride, and a (prims in ship)-30 attachment that you wear. This is how it works with a ~220-prim helicopter I have. Attachments don't count against the prim limits of a parcel, so you can fly above smaller (or more full) land without incident, assuming it has the 30 prims to spare for the physical part. You can't land and get out, or the ship might detach, depending on how it's scripted. Also assuming the ship doesn't momentarily detach in flight, or it will disappear. I've had this happen often. Beware of sim crossings, and especially sim corners. Hit a corner and you'll probably have to relog.

Ah so.

Basically it means, that it is not possible to use the ship as a home in SL.
But how can peoples get in the ship ? When I looked at the pictures, it seems that the whole ship is designed for several peoples. There are chairs, beds, living room, the bridge etc.

You can have pose balls as part of the physics-enabled part of the ship. My helicopter seats 12, for example. It would work for the spaceship too (if that's what you're looking for, the helicopter guy makes a smaller space ship that I know to be flyable, with some passenger accomodation. IM me in world). You can use it as a home, you just need someplace really big to park it.

Hmm, "pose balls", "physics enabled part of ship"...

It seems that I need further reading of some faqs and threads. I have a relatively good background in 3D modelling and graphic, but I am a total newbie in this game.
I thought that the Havoc physics engine is a base of SL and physics works everywhere. So I supposed that if you build such a big ship, peoples (avatars) can normally enter inside through the door, go everywhere they want, sit on chairs, dance on tables, sleep in beds etc.

It would seem that way, but in practice that doesn't work every well. Look at how generally bad elevators are. You can't stand on a moving prim and be moved with it. That's what the pose balls are for: they attach you to objects so you can move with them (in this case). Even more, avatar attachments go phantom, so anybody not on a pose ball would fall right through the floor.

I'll give you a more simple example.

I own a pirate ship. The ship itself is a 27-prim stripped-down hull. When I rez it, the ship rezzes an additional 250-prim placeholder piece that is the rest of the sails, rigging, masts, and the like. Yes, the parcel I rez it on must have 277 prims free, or the ship won't fully rez.

When I 'get on' the ship, the 250-prim part is replaced by a 250-prim attachment, and I'm actually riding a 27-prim hull. There's room for up to 4 more people to get aboard after me, and they end up standing at each of the gunnery stations, behind the cannons.

I can now sail that ship anywhere, regardless of prim count, because the ship is an attachment on my Avatar's pelvis. It's like wearing a VERY complex furry avatar. As long as I am 'driving', the vehicle does not count against local prim limits. But I also can't get out of the driver's position.

When I stop somewhere, it HAS to be someplace with at least 277 prims free. If not, when I, as pilot of the ship, get off, the ship tries again to re-rez the 27-prim hull AND the 250-prim static sails. Not enough prims? It fails to rez, and it looks like my ship is a wreck. What's worse, if I land on a parcel that I own, a glitch in how SL handles vehicles "dropped" on the oener's property could cause OTHER prims on my parcel to vanish. Like my HOUSE! I pwn this ship because precisely thgt happened to one of my island tenants. He bought this huge ship, rezzed it on the ocean where there were enough prims, and when he tried to dock it on his beach, the ship wrecked and took his house with it!

So... for a huge ship like that spacecraft? Yeah, you'd need a LOT of land to launch or land that baby!

I see. So, it means that even if you have a pirate ship, you cannot take several friends, go to the sea and suddenly say "look folks, I need to do something else. My boat is your boat, in the meantime you can sail here and there and please anchor the boat in my port when you will finish." Right ?

Sorry for my stupid questions, but my english is far from perfect and also I still tend to see the whole SL as a one big Softimage (Maya, 3DSMax etc.) scene. I had the ilusion that everything what is build is persistent if it is not deleted by owner.

Not all large ships use an attachment system though, the one she is talking about uses a version of the multi-prim movement scripts that are out there. There are a couple of different ways of doing things. You can attach extra pieces to yourself via an attachment like everyone was talking about, there is a script out there to allow you to do a non-phys. ship (AubreTEC's Osprey for example), or a multi-link script that allows you to link multiple linked objects together (this is the script the large ships are using that you are seeing).

Yes, I understand that there are several ways how to skin the cat, but if I understand correctly, the basic principle is the same.
When you are buying the ship, basically you are buying an illusion of ship.
The ship is not a real (well, "real" in SL world) heap of textured prims which will persist in SL even if you are off-line, right ?
I cannot log off and let my friends to make a party in the living room of the ship floating somewhere.

Eudoxus, the answer to your question of whether or not you can leave the ship somewhere depends on a few things. The first factor is what kind of a build it is. If it's something that depends heavily on avatar attachments to give the illusion of a large moving craft, then when you exit the world, the attachments will disappear along with your avatar. However, if it's just a plain old (normal) build, then it will stay wherever it's put, assuming the owner of the land it's on doesn't have a problem with it being there.

And that brings me to the second factor, which is land. As has been explained, SL allows 117 primitives for every 512 square meters of land (15,000 prims per region). In order to place any object anywhere in the world, whether it be a ship or a house or a sculpture of your dog's hairy butt, the land has to be large enough to support the total amount of prims of which the object is made. For a 2000 prim object, you'd need an eighth of a region, or 8192 square meters, as you seem to understand already.

As for making the ship move, that's a different story. The problem is that the physics engine has a limit of 31 prims per physical object, and 256 prims per non physical object. There's simply no way to have an object made of 2000 prims behave completely as a vehicle. The effect has to be faked.

There are lots of different ways to do the faking, but none of them are particularly good. The avatar attachment method will produce the most fluid movement, but since attachments are completely nonphysical and intangible, most of the ship won't be able to collide with anything (including people), and it won't persist when the pilot leaves the world. (The persistence problem can be handled by scripting the vehicle portion of the ship to rez a temporary copy of the missing parts when the pilot leaves, and then kill those parts when the pilot boards, but it's a lot of work to set all that up.)

The multi-move method gets around the attachment problems, and leaves the whole ship tangible, but it's not very fluid. Movement tends to be a bit inchworm-like, as the various parts scramble to catch up with each other. I'd imagine the coming implementation of Mono will help with this greatly, as it will tremendously improve the speed at which scripts run and respond, but that's obviously just wishful thinking since none of us have really seen what Mono can do for SL yet.

Basically what you're discovering here is that SL, like anything else, is not perfect. It has its limitations. The creation of large objects has always been challenging. It's expensive in terms of both land and creative development, and it's functionally prohibitive.

No object can do everything you want it to do. Everything's a balancing act. If you want something to be a vehicle, it has to be relatively small. If you want something to be highly detailed, it might not be able to have much function other than just to look good. The key is to consider seriously what features are most important, and to build efficiently for just those features.

Anyway, if you want to see some examples of large, persistent ships, come by some time and visit us in Indigo. Hovering above the Sci Fi Museum in the Northwest quarter of the region, you'll find a Klingon Bird of Prey, and USS Defiant. Both ships are full size, fully explorable, and as accurate to canon as possible. (Note that they're both still under construction, so you'll have to forgive some of the texturing and various missing items/features, but there's certainly more than enough there to show you what's possible.)

The only thing they can't do is fly. That's fine by me though since there's really no reason for them to need to go anywhere. Various Star Trek fan groups use them for roleplay events and such, but mainly they're just museum exhibits, and that's all they need to be. I've never seen any potential benefit in the prospect of tooling around town in hundred-plus meter long starship. Even if it were possible, it could never be practical.

So, to give my answer to your original question, "what's the difference between a ship and a house", in my case, there is no difference. A build is a build is a build. Two of the three large structures on my property happen to look like starships, and the third happens to look a building. They're all just collections of prims, textures, and scripts though, and that's all they'll ever be.



EDIT: Oh, and if after all this, the house vs. ship question is still bugging you, well, you could always just get yourself one of these:

Build a "ship in the bottle"... 100 prims at a time on a 512 land.

Scripts can then reassemble it on an appropriately larger land.

You can, as long as that 'someplace' is somewhere where you're allowed to keep 2000-odd prims rezzed indefinitely. I don't imagine you could let somebody else fly it because they'd have to be wearing the bulk of the ship. Many cars have guest/group/open driver settings, but they aren't attachments.

Chosen Few: thank you very much for your long post.

Now, I undersand it. Simply, from the point of view of "reality" in the SL world, anything beyond 117 prims per 512 m2 is fake.
No problem, I can live with it.
But maybe, the creators of large ships/vehicles should say clearly in the ads that their models are fake and not "real". I mean "real" in the reality of SL, of course.

But....they ARE real. This whole discussion was about the general feasability of a 2000-odd prim MOVING craft and the tricks you have to pull to get it to work. I still think that the craft you are talking about is entirely static (Have a link to the slexchange page? I'm curious now). A house that you stick somewhere big enough to hold it. Even attachment craft can be rezzed and left alone while you sign out with the right scripting, like that helicopter I have. '117 per 512'* is just a ratio...things can scale. I myself have made a castle that's nearly 600 prims. It's real (and spectacular )...I just never have anywhere to put it except the sandbox where I work on it!

* Offer not valid in Grignano, Sistiana, Miramare, or Barcola

The ship is here:

http://www.slexchange.com/modules.php?name=Marketplace&file=item&ItemID=136592

Eudoxus, you seem to have misinterpreted my use of the word "fake" in my post. Sorry if it wasn't clear.

In no way did I mean to imply that there's anything "fake" about large builds. As I said, a build is a build is a build. They're all equally "real".

If something is composed of more than 117 prims, then it simply needs to sit on land that's larger than 512 square meters. That doesn't make it fake, just big. Big things need more land. That's it.

What I was talking about with the word "fake" were the techniques involved in getting large vehicles to move. Technically, a "real" vehicle can only be 31 prims (and each passenger counts as one), so any vehicle larger than that is not entirely a vehicle under the physics engine's definition of what "vehicle" means.

For a large object that is intended to behave as a vehicle, the appearance of vehiculation has to be "faked", but the object itself is still entirely "real". My definition of "fake" in this context simply means that clever methods are employed to get around the limitations of the physics engine. Again, that doesn't mean the build itself is somehow not real. It's as real as anything else in SL, no matter what functionality it does or doesn't have.

Perhaps I shouldn't have used the word "fake" at all. I probably could have and should have picked a better word. I hope I haven't confused you any further.

As for the ship in your link, If I had to guess, judging by the ad description, I'd say it's operating is by having pilot wear a HUD device that controls all the various parts of the ship. The ship itself is likely divided into sectional modules, each one a linkset, and each one containing a script to listen for commands from the HUD. When you press a button on the HUD, it shouts a text command to all the various pieces, telling them where to go and what to do.

If well written and implemented, the HUD control system could be very effective, at least in theory. I would suspect there's probably still a bit of "inchworming" happening when the ship moves, but it's probably nowhere near as severe as with more traditional multimove methods since there's no one section of the ship itself operating as the master. All sections are slaves to the HUD, which is invisible, so can't be seen to move faster than the other parts.

In retrospect, it's an obvious good idea, but it's one I had never thought of before. I guess that's why I'm not a scripter.

As for your suggestion of a disclaimer on ads, that's a nice thought, but is it really fair to expect every ad to explain every aspect of SL that every newbie might not know? I think you'd agree that's not the purpose of an ad. An ad functions simply to showcase a product, not to explain how how the world works.

Think of it in relation to how RL ads work. In RL, a car commercial won't bother to say that the buyer will need a driver's license to operate the car, or that it will require oil changes and other maintenance, or that it won't work underwater, or that it can't fly, or that it's not impervious to nuclear attack, or how many clowns might be able to fit inside. Of course all of those things may be important to know before your decide to buy a car, but it's not anything anyone expects a car commercial to explain. Most of those things are simply facts about the world that apply to cars in general, not anything specific to the one car in the ad. Such universal teachings are well beyond the scope of an ad's purpose.

By the same token, an ad in SL can't be expected to teach how the SL world works. It's not the advertiser's responsibility to make sure that you know how much land it takes to support any given amount of prims, or the nature of how the physics engine operates, or anything of the kind. That's general worldly knowledge covered in the SL instructions (and on these forums). As an SL user, it's your own responsibility to learn the basic natural laws of this particular universe, and apply that knowledge to your purchasing decisions accordingly.

So this big ship is not a "real" vehicle, so what? It's still a real build, and it still (presumably) does everything the ad promises it does. It just doesn't use the physics engine to accomplish its tasks. That's really not a big deal (the physics engine kind of sucks anyway).

Now you might say, "Well, it would only add one more line to the ad to mention that it needs to be parked on X amount of land, and that it's 65 times too prim-heavy to be physics-enabled," but think about all the other possible things a newbie might not know. Those two facts may seem crucial to you because of your own direction from which you first approached the subject, but understand that each of the thousands upon thousands of new people who enter SL every day will all have entirely different questions, different assumptions, different preconceptions, different misunderstandings, and different subjects they consider to be equally crucial.

You can't expect any advertisement for a product to anticipate every possible thing someone might not know, and explain it all. If they did, then every ad would become a 300 page instruction manual.


Anyway, I hope this has been helpful, and that I have not confused you any further.

Thanks to all for very interesting posts

Chosen Few: yes, you are probably right.

Because I am total newbie (and 3D graphic oriented a bit), I tend to look at SL as a regular animation program like Softimage (or similar).
So, when I mean "real", I mean something what is really sculpted from primitives and/or solid meshes, textured and can be used anytime, anywhere in any situation.
"Fake" is everthing else. Maybe, the right terminology is different in english, I do not know (as I said, my english is terrible), so I will use the example.

In 3D animation program, you have basically three ways how to make let's say a model of football (soccer) ball.
1. Use a very detailed mesh, with sewing etc. If you do it, the ball is "real" (in the context of the animation program) and you can do anything you want with it. Scale it, apply laws of physics to him, put it on any other object in the scene etc.
2. Use simple sphere and clever set of textures (material, bump map, shinines map, opacity map, several layers of various other textures like dirt etc.). But it is "fake", because you can't use it anytime, anywhere. For example, if you move your camera close to the ball, you can see that the horizont of the ball is flat, because only few renderers are able to use bump maps on horizont.
3. You can draw the ball in 2D and use it only during post processing and compositing. This is total "fake".

So, if I understand the whole thing correctly, from my point of view only houses with max. 117 prims are "real" (or better to say "fake" a bit, because if you have windows made with opacity map, you cannot position your avatar sitting in the window with legs outside to the street).

This would describe most objects in SL. Very simple mesh with a texturing providing the appearance of detail. Your soccer ball in SL would function best as a simple sphere with all the pentagons and hexagons textured onto it. If you tried to make it out of real pentagons and hexagons, you'd need to use 84 prims (2 for each pentagon, and 3 for each hexagon). There's obviously no way to justify that amount of resources for such a plain object, not to mention that it would be well outside the range of what the physics engine can use.

Anyway, I might suggest your outlook on what is "real" vs. what is "fake" could stand some retuning to allow for the difference between modeling for real-time and non-real-time applications. If you want to model a soccer ball for a film or for a still image, by all means, give it several thousand polygons, exquisite bumping, all the rendering tweaks you can muster, the whole nine yards. If it's for real-time though, like for a game or for SL, then it makes sense just to use a simple low-poly sphere, painted with a soccer ball pattern.



I'm not sure why you seem to be hung up on the 117-prims thing. Maybe I'm missing something in what you're saying. 117 is simply the maximum amount of prims you can put on 512 square meters of land. It's not a maximum for houses or ships or anything else. If you have more land, you can have more prims on it.