Rotation 'Hinge' Trick and Workflow

I hate that you can only rotate a prim around its centerpoint. But there's a workaround.

If you want to create curves, you'll appreciate this trick that faux-offsets your prim's axis of rotation to create a 'hinge' effect, with the result being flowing multiprim shapes.

1. Create Box 1 where you want it. For this example make it smaller on the y, like a wall segment.
2. Create a dupe of Box 1 with the 'Copy' trick or by shift-dragging with Box 1 as reference (shift-g makes an object a reference object). If you did the copy trick, it creates Box 2 precisely 1 step over from Box 1. Box 1 remains selected.

You now have two wall segments flush next to one another.

3. Reselect Box 1 and shift-drag-dupe it again, preferably by shift-dragging backward on the Y (no control-z yet, for those who know). You've moved Box 1* behind from your new Box 3, next to Box 2.
4. Select Box 3 (remember, it's the one still in place).
5. Drag the resize dots with 'Stretch Both Sides' unticked. Resize it down to .01 on the Y and .01 on the X. Box 3 is now a 'thin prim' on the X and Y while still being tall on the Z.
6. Select and link Box 2 and Box 3, with Box 3 as root prim.

Now you'll see why we've kept Box 1 off behind--otherwise selecting that thin prim is a pita. Keep this linked set selected.

7. Using the Edit tab's rotation boxes, enter a Z rotation of -20 for example.. It rotates around the center of the thin prim, Box 3. So you've essentially used Box 3 as a 'hinge.'
8. Unlink and delete the 'hinge' so as to save on prims.
9. Select Box 1 and NOW do a 'control z' to put it back in place next to Box 2.

There, you've rotated your Box 2 around Box 1's most +x and +y. Your hinge was Box 3, and now it's gone. Actually to be precise, you've rotated around .005 of that point, but I'm not going to muckymuck with that. This can be fixed by moving Box 3 half it's width on the X and Y so that its centerpoint is precisely at the corner.

As an option, you can create chains of prims with their thin-prim 'hinges' and link them to create smooth curves. A lot of scripts exist to do this also, but for those who prefer the manual way, this is blazing fast once you get your keystrokes to 'robotic' state.

I'm sure more experienced builders have discovered this trick and others for themselves, and that I'm recreating the wheel. But my theory is that it's always good to share what you've learned, and this has been a freaking gas since I sussed it out a few nights ago.

Gawd, I hope I kept my box-numbering right!

_________
*Yes, Box 1, because when you dupe a prim by shift-dragging, you move the original, while the dupe remains in place.

That's hard to follow. Is this an accurate summery:

1) make door in whatever shape you like
2) make a thin prim "hinge"
3) Link door and hinge with hinge as root

Now when you use a door script the rotation is around the axis of the "hinge" prim.


If that's not what you're describing.. well, it's still a good trick for static builds with fancy doors! *laughs*

That's shorter, yeah.

But not what I'm saying.

I'm not trying to be ProkoLogorrhea Nevy here; I'm trying to boil it down to fewest keystrokes, which is something that people who do 3d for a living sometimes try to do. You're talking about doors, and more power to you because, god knows, doors are great. Raise a glass to doors! Here's an extension so you see where I'm going:

Make a line of prims with their thin-prim hinges. That'd be after step 6.
Link the whole lot with the leftmost thin prim as the root.
Rotate -10 degrees.
Repeat down the line, using each thin prim as the 'hinge' for the remaining prims.
Delete all the extra thin prims.

Whatcha got? An arc of many tens of meters in length!

Reverse the rotation in there somewhere by rotating the remaining line of prims on the x axis, whatcha got? A parabola!

Your use of the word "hinge" is confusing. I use this technique often and I use the word "pivot" for the object used as center of rotation.

Donno if this is of intrest here,,

Instead of making a child object (door) and attaching it to a pivot object (hinge) Just make a "door" twice as wide, and twice as thick as you need (but only as tall as you need) then use your "cut" spinners to reduce it down to a fourth of it's size (basically decreasing it's width and thickness by half) and you get a prim with a pivot point on a corner instead of in the middle.

You have just increased you slab door efficiency by %100 >=)

In addition to reducing keystrokes, we also look for ways to reduce our poly counts

Donno about curved, or shaped doors, haven't had to build any yet.