objects bumping other objects causes problems in sims?

So I bought this scripted cat that walks around and will usually turn around when he bumps into something. I logged in today to find him returned to me along with all his toys saying that it was messing up the physics and causing problems on the sim...upon asking for specifics I was told that it was because the cat and his toys were bumping into things and that was messing up the physics and other stuff in the sim...

anyone understand this or have more information about this? It sounds to me like you can't set anything to physics and have it bump anything else without messing up the sim? Sorry for my less than technically apt brain, I'm just trying to find out why this is suddenly a problem as I have had the cat for months.

any insight would be welcome!

In moderation, a little bumping is alright. But a complex (particularly with moving, round surfaces) item repeatedly bumping into things overloads the physics simulator in each sim. How this impacts others is what is in what is known as time dilation. Idealy, time dilation should be at 1.0. But the physics engine has a nasty habbit of hurting time dilation more than most things -scripts, for example- do. A physical object repeatedly bumping can drop the time dilation down quite a bit... ANywhere from .99 to .05, depending on how much / how often / what shape / some other specifics. At .99, the time dilation issues are almost nill. But start to get around .95 or lower, and it becomes noticable... Everything starts moving very slowly, like slow motion... Avatars, other objects, etc. After it passes .8, the sim is basicly a very very un-fun place to be... Even .95 isn't all that thrilling.

Reitzuki speaks the truth.

I had similar probems when I built my giant aquarium. The (physical) fish were scripted to turn around when they bumped into things. This worked great, until they got caught up in corners and dragged the sim to a halt. I also logged in to find half of my "stuff" returned to me by a Linden who was trying to determine what the problem was.

I ended up solving the problem by cutting down the fish population and moving the most notorius fish to a private tank with round edges (no corners). No more lag, no more problems.

2 questions:

1. Who was the "expert" who returned your cat and made the statements regarding physics problems?

2. Don't moving vehicles "bump" into things? I play water polo egularly..thats 8 AVs 8 vehicles and a physical ball. All are contained in a 400m^2 area and they are constantly bumping into each other, walls, the ball. All innertubes are made of torii and the ball is a sphere.

So, tell me? are we causing problems for the sim, or are we enjoying our SL experience respectful of others and within the standards of the TOS?

If it was a non-Linden who returned yout cat then tell them to bite you. If it was a Linden, I would expect a better explanation.

I think physical stuff is generally ok, but not such a great idea to leave it unattended.

1) Bumping into the ground is much "lighter" on physics than bumping into objects
2) Vehicles are generally well behaved when it comes to bumping. Collisions are easiest to handle when the object resembles a box or a sphere -- uncut cubes, spheres, and cylinders, and the outer edges of toruses all count.
3) Neither of the above is always true -- witness some of the early races held by the SLRA.

Thanks for the responses Carnildo, Olympia, blaze and Reitsuki.

Yes, as many said here, generally, the few bumps here and there are fine. Infact, often a sim can handle a bit more then a few. Generally a sim can take a fair amount of pounding in the way of phyiscal objects colliding with others, BUT, certain key shapes are harder on a sim. Generally, anything with a rounded surface can create some quite interesting effects. Infact, this can be such a problem that is causes a sim to go into a "deep thought" state where, it takes exobatant amount of time to calculate what should be happening and can even cause a sim to go down.

As for the question of vehicals, generally they are colliding with the ground, which is a much easier collision calculation to make in comparison to certain prim to prim collisions. As well, for the most part, vehicals do use more of the simplistic shaps to obtain their shapes. I have found thru direct exeperience that when using specific shapes like cut torii in a vehical, this can cause some quite unpleasent effects apon the sim.

Finally, Reitsuki nailed it on the head, there is the factor of time dialation. There is an extra number as well, which is the Physics FPS. This value indicates how often a the physics calculations are occuring per second. Generally, on any given sim its normal to see 43-45, but when things are getting extremely busy or complicate, you may see it drop below 40, which usually signifies a problem of some sort. Note, an exception to this prognosis is sims laden with tons of people, but thats a whole other ball of wax.

There is some promise in the future in the form of Havoc 2 which promises us some releif from all of this. The primary plus is faster physics calculations and elimination of "deep thought" which for agressive physics users and objects should add a little more "play" in what is excessive.

For the time being, when you're going to log for the night, its probably a good idea idea to pack little Kitty in her crate for the night.

Generally the cats move around fine. It can happen though they get caught under/in another item. Usually they try to work themselves free by turning around (on a limited timed basis, to prevent a multitude of bumps). But sometimes they keep getting stuck. (continuous bump) This can cause an overload on the server, due to it having to handle a lot of complex collisions, or the dreaded 'deep thought' (the physics engine goes into some kind of everlasting loop, eating up all sim cpu cycles, which basically is a Havok1 bug).

I have tested them over longer periods of time having over 10 of them running around at the same time. There are definitely some issues with physics items in SL, especially when they contain internal rotations. I tried to find workarounds for most of the issues, but there is a lmit to what can be prevented.

Normally it's not a good idea to leave autonomously moving physics items out unattended for too long. To prevent this from happening, I added a sensor to the cat that will put it into a non-physical, low lag, 'sleep' mode when there is nobody around. (I know a sensor is laggy, but a moving physics object is much laggier.) In crowded or busy sims, it seems this doesn't work too well, as it never falls asleep.
In these cases, people can purposefully make it sleep by just ordering the cat to do so.

If the cats caused any grief on anybody. Then I am sorry for that.

Damanios, just an idea, but is it possible to script the cat so that it "sleeps" whenever the owner is offline?

This was not meant to be a complaint thread, just a search for information as to what was going on. Anyone in Batak who had sim problems because of my kitty I'm sorry!