From: Crash Kyaw
We all know that primitive objects are either independent, or grouped/linked with other prims through a central prim. Someone suggested changing that, so that more than one prim in an object could be considered “central” to a particular set of prims.
What you may be referring to is the allowance of multi-tiered hierarchy in the linking. Right now, we only have one tier, consisting of two levels, parent and child. In other 3D modeling applications, you can have unlimited tiers.
A good example of a multi-tiered hierarchy is a human skeleton. Your fingers are children of your hands, which in turn are children of your elbows, which are children of your shoulders, etc. Rotate your shoulder, and everything that's lower in the hierarchy (your entire arm) moves along with it. Bend your elbow though, and your shoulder is not affected. Your hands end up moving with your elbow because they're lower down in the hierarchy, but since the shoulder is higher, it doesn't have to care what the elbow is doing at all.
Another example would be a bicycle. The rear wheel is a child of the pedals/gears. Spin the pedals, and the wheel has to spin too. Spinning the wheel on its own though doesn't make the pedals move. That's what allows the bike to coast. Both the pedals and the wheels are children of the frame, which is why when you pick the frame up and move it, the pedals and wheels go with it wherever it goes.
In SL, sice we only are allowed single tiered hierarchies, skeletons and bicycles, and all kinds of other things, are impossible to make. You can fake some of it with clever enough scripting, but it's not the same thing.
Many of us have been asking for multi-tiered hierarchy for a long time now. I once asked Cory Linden about it a couple years ago. His response was "Our initial thinking was 'nature doesn't have hierarchy, so why should we?' That thinking was wrong, so we'll change that." That was well over two years ago. How many tiers do we have now? Still one. Frustrating.
From: Crash Kyaw
I would like to also suggest that we have NUTS & BOLTS. As a prime example for this, you cannot take a flexi object, and attach something to its “end.” But if there was some “special linkage” you would be able to attach a prim to the “flexing” end of the prim, and it would move in relation to the objects end, rather than the objects “beginning.” There is no way in SL to create a ball of twine at the end of a string. You can only have string extending from the ball of twine.
Ultimately, you cannot have a piñata, and that’s a crying shame.
You seem to be misunderstanding how flex works. The reason you can't have a ball or a piñata on the end of a flexible string is because the flex is just a client side graphical illusion. It's not really happening. As far as the server knows, that floppy, flexy sting is just a straight cylinder.
All the physics in SL happens on the server side, and since the server has no idea what flex is, there's no way for it to calculate how to dangle that piñata around on the end of the string. As far as the server knows, the sting is always straight, so anything attached to it has to stay put. To get it to do what you're talking about would require a fundamental redesign of SL's architecture.
From: Crash Kyaw
How it works:
You allow for two types of “connectors,” call them what you like. Pins and Pivots… Whatever…
Bolt
One type bolts one prim to another prim. This is similar to the false system we have now, but in this case the prim would exclusively map its location only in relation to the prim it’s attached too.
Hinge
The other type is similar to the flexi prim, in that it reacts to the local physics that are set. This creates a loose connection that can function exactly like a flexi prim. Probably with the same set of parameters we use with flexi prims.
Just thought it would be interesting to see. Maybe there’s something I haven’t learned in SL that does this… Lemme know if so…
(I’m making a proposal for this so please consider voting for it.)
Proposal:
I would like to create some sort of “BOLT” that would attach one prim to the next, rather than all prims being mapped from the central prim. This would include being able to attach a solid prim to the “loose” end of a flexi prim. Also, I would like to be able to have that bolt be “loose.” This would allow multiple linked prim (objects) to “fall” toward the earth, depending on their position in space. An obvious example of this would be a bag (purse, briefcase, etc.) that, when held, still “hangs” down.
We used to have joints in SL back in the day. There were several types of them, and some worked similarly to what you're proposing. They didn't require any extra prims though. They were simply an alternate method of linking prims together. We had the solid link that we still have today, and a jointed link with a selectable range of behaviors.
Joints were ultimately removed from the system a year or two ago because they were difficult to use, very prone to breaking, they were taxing on the physics engine, and they were rarely used. It would be nice to see them return one day, but don't hold your breath. They've got much bigger fish to fry over there at LL first.
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