link with hinge question

New to SL and having read through several tutorials and guides I decided to try make my own lounge chair with a back that could swivel between upright and flat position. For the back I added a small cylinder that I use to set the hinge pivot point. With the 3 back prims linked this unit when rotated does just what I intended.

How do I link this back unit to the rest of the recliner without causing the whole chair to rotate instead of just the back as intended? Does this require some kind of rezer script such as are used for houses? Any advice or points in the right direction are most appreciated

Since SL, unfortunately, has no tiered hierarchy in the link setup, there's no practical way to make the three prims of the chair back rotate the way you want. Here are four options you could use as a work-around:

1. Keep the back as a separate linkset from the rest of the chair. If the chair needs to be movable, then I'd suggest you script the chair base to rez the back, and script the back to keep itself positioned properly, relative the base.

-OR-

2. Instead of three prims, make the back out of one single cube. To put the pivot point in the right place, simply cut the cube in half, so that the center becomes an edge. This is how doors are typically made.


-OR-

3. Same concept as #2, except instead of using a cut cube, use a sculpty. In your 3D modeling program of choice, simply shape the mesh so that the object's pivot point is at one of its edges.

-OR-

4. Create two copies of the back, rotate one to the upright postion, the other to the flat position, and then link them both to the chair base. Script the individual prims in each back to turn visible or invisible on command. The command that turns the three "upright" prims visible should turn the three "flat" prims invisible, and vice versa. As long as both backs are never visible at the same time, the illusion you're after will be maintained. You won't see the rotation animation happen, but you'll have your two positions, which is the important part.



Incidentally, LL's former CTO told me two years ago that the lack of tiered hierarchy was a mistake in their original design plan for SL, and that they would be adding it in. He said, "Our original thinking was 'nature doesn't have hierarchy, so why should we?' That thinking was wrong, and we will correct it." Yes, that thinking was very, very wrong. But two years later, here we are. That person is no longer the CTO, and we still don't have hierarchy in SL. I have no idea if we ever will.

Chosen, thanks for the quick response. I’ve learned a lot reading many of your helpful replies in other posts. I didn’t realize that cutting a cube in half to move the center point to the edge (as listed in option 2) was even possible.
If I went with option 4 would my script that changes the prims invisible properties need to change the “phantom” to solid property at the same time or if my animations are setting the pose do I even need other than phantom? What I hoping to make is a beach lounge chair that will have a couple of animations used in the upright sitting position where my avatar applies suntan lotion or just sits and than when the chair back is in the flat position AV will sunbathe on either stomach or back.
Since I am only doing this for myself on my beach front property you have given me a few options to try out so thanks again.

Look into a product called "Puppeteer" it will animate a set of linked prims on touch command. IE save the steps in the animation, touch play forward, touch play back. This will animate your chair, hey I made a pull out bed/sofa that was fairly realistic with that kit. It's full perms and made for builders. Fairly simple to use.

Just to clarify, you're not actually moving the center. What you're doing is removing half the prim, so that the center becomes an edge.



Two things. First, you can't have part of a linkset be phantom, and another part be tangible. It's either all or nothing. Second, it doesn't make any difference whether or not the chair is phantom. A sit target will always park the avatar at a specific distance from the center of whatever prim the script is in. It doesn't matter if there's another prim in the way. Depending on the XYZ values plugged into the script, the avatar could end up sitting on the prim, in mid air, inside a brick wall; it makes no difference.

That said, I usually make chairs phantom, especially if they're indoors, so that people don't get stuck trying to walk around them. But that's strictly an ease of navigation concern. It doesn't affect the actual sitting in any way.

LOL I did too

Yes you can... even you still have things to learn, it was actually in my opinion a quite well known trick.

Flexible.

I used it in a product even, for my tiered hierarchy turret on a tank to prevent the barrel getting stuck into things, the only problem is that the primitive type options get restricted down to box, cylinder or prism.

How did I know someone was going to say that? I guess for completeness' sake, maybe I should have mentioned it, but since it wasn't an appropriate solution for the question at hand, I didn't really see any point in bringing it up. So I have to give your answer points for totality, but not (at least in my opinion) for relevance.


There's no need for the personal snap. Look, of course it's well known. I just don't recommend doing it for things like this.

As was discussed fairly extensively in a recent thread on pool-building techniques (I guess you missed that one), even with settings at zero, flexi-prims still end up flexing sometimes, especially when moved. And since it's purely a client-side effect, you can never really know if what you're seeing is the same as what everyone else is seeing. While that gun barrel might look perpetually stiff to you, it could well look floppy at times to someone else.

Call me 'not in the know' if you want, but I had the sneaking suspicion the OP wouldn't be too happy if her chair back were to turn to jello from time to time. With that in mind, what specific benefit to this particular thread would have come from my suggesting flex?



And by the way, yes, I have lots to learn, just like everyone else.

Atom, thanks for the tip on "Puppeteer". I got hold of the free version to give it a try.

Chosen,it looks like keeping my chair phantom is going to work out fine for me. I really don't need to stand on the chair unless it's to get a better view of the fishies swimming in my ocean