If you are a builder or scripter then you should check this out!

[ST33LDI9ITAL]

https://jira.secondlife.com/projects/BUG/issues/BUG-232445?filter=allo*****sues

Take the time to read this and add a comment if you support it (which you should) because this would be monumental for SL. This is a proposal for adding the ability for linksets to have hierarchical support. Child prims for child prims essentially. Why is that a good thing? Well, because it would make building any sort of complex build, gadget, vehicle, whatever that uses rotations, hinges, pivot points, soooooo much easier and more accessible to people. It would be an amazing upgrade for building. A much needed upgrade, all around. So go on, be vocal! If you want change ya gotta make your point heard! Comments here are great, but comments on the jira ticket are much more meaningful!

[animats]

Adding pivot points has come up at Creator User Group several times. The idea is to be able to make doors pivot around any point. I suggested extending this to support a general hierarchy, where child prims can have children of their own. Something just about every other 3D graphics system has. Philip Rosedale has said this was his biggest design mistake in SL.

It turns out that the way server to viewer messages work, this might work now. It doesn't require changing the UDP message format, which is a big deal. The messages are all of the form "I'm prim B, and my parent prim is A." When you have a seated avatar with an attachment, you already have three levels. So the viewer seems to support this.

There are limits to what can be done in the existing system. See the JIRA. We're not sure yet how hard this is server side, which is always the hard problem. It might be easier than pivot points, which generate a lot of special cases. What if the pivot point is outside the object?  What's the pivot axis? What happens when you rotate the prim in the editor? Stuff like that. With a simple hierarchy, you know what's supposed to happen. Everything is visually where you expect it to be.

With this, if you wanted to do a swinging door, you'd place a hinge where you want the hinge line, parent the hinge to the building, and parent the door to the hinge. That defines the axis of rotation in a very straightforward way. No calculations necessary; you can do it visually.

It's also a step to being able to import hierarchical models from 3D sites into SL without losing the structure. Discussions at Creator User Group indicate that LL is leaning toward GLTF import for materials. GLTF also has a hierarchy, and so, the closer SL matches GLTF, the easier imports get.

Anyway, that's my take on this.