Rotation Help

I'm trying to make a parasol using 6 hollowed cylinders with their path cut at 0.25 and 0.75. I'm getting close to what I want using the different ruler modes but I cant get the edges aligned very well!! Is there some sort of mathematical formula I could be using to help with the rotation of the pieces?

I've included screenshots so you can see what I mean....thanks for any help.

Well, the view from the top looks fine. Better, in fact, than many I've seen. You can make the joins look a little cleaner by making the texture on the cut end of each segment a blank white instead of using the striped texture. That will at least take care of the problem when you look from the top down. I imagine that the underside is where the mismatch really bothers you, though.

If it were my build, I might be tempted to cheat at this point. Even though it adds prims, it might look good to bury a long, skinny cylinder right along each of the joins, extending them out slightly beyond the parasol the way splines on a real one would. Choose the diameter of these new cylinders carefully enough and they'll disguise the slight mismatch that has you worried.

I made a few tents and large structures. Just use the edit window and adjust the XYZ variables mathmatically at a VERY close view. Thats the best you can do really. Mine are always mathmatically imperfect, but seamed well. I am not big on absolutes anyway, I prefer things to be made slightly naturalistic and flawed.

Here's a trick. Use another prim as your pivot point. Here's how:

1. Start out with just one parasol section (PS), rotated so it's level. Rez another prim, and center it exactly at the PS's tip. The centering will be easy if you use the reference ruler. Simply select the PS, press shift-G (with chat closed) to reference it, and make sure Use Grid is turned on in the editor. Then you can easily snap the other prim into place via the on-screen rulers. Make sure to do it on all three axes. When you're done, set the ruler mode back to World. We have no further need for Reference mode at this time.

2. Link PS to the other prim. The PS should be the child in the linkset, not the parent.

3. Using the editor, not the on-screen manipulator, rotate the linkset on X or Y, to whatever roof pitch angle you plan on using. Judging by the very near success shown in your pictures, you should already know what this angle needs to be.

4. Unlink the two prims, and reset the base prim's rotation back to 0,0,0. Then re-link. Again, you want the PS to be the child, not the parent.

5. Now, duplicate the linkset by shift-dragging it any direction to leave a copy behind. Then press ctrl-Z to undo the movement of the original, returning it to the exact location of the copy. In the editor, rotate the original by 45 degrees on Z. The alignment between the two sections should now be perfect.

6. Repeat the duplicate-and-rotate procedure six more times, and your parasol will be complete.

7. Unlink everything, delete the extra prims, and link the parasol sections together.



So you know, the reason it was important to use the editor for the rotation, and not the on-screen manipulator, is that when you type in the numbers, the pivot point is the center of the parent prim. When you use the manipulator, the pivot point is always the geometric center of the entire linkset. By temporarily linking to a throw-away prim, and using the editor for rotation, you can effectively move the pivot anywhere you want. In this particular case, the pivot needed to be at the tip of the parasol section, since that's what in the end is the center of the whole parasol.

The entire above procedure should take about a minute or two to complete. Enjoy.

Chosen, that is a great explanation. Thank you. I learn something every time I read one of your posts.

Thanks for the help guys...it helped me finish the build.

Chosen, that was a really simple explanation to follow and it worked perfectly and you were right it did only take a couple of minutes to do.

I also used that method to make the spines like Rolig suggested and I'm happy with the final results.

Roliq and JoeH:

It would seem you haven't visited the Ivory Tower Library of Primitives. I suggest you do a search for it in-world and head there, it's got some wonderful tips.

I say this because what Chosen just described is taught there (Though using images and such, as wording it can actually be hard..well done Chosen!), as well as a bunch of other useful tips.

I always suggest builders go there, as even if you've been around forever, the things there might be something you haven't thought of, or have just plain forgotten about.

Anywho yeah... if you feel up to it, check it out ^_^ it's a large, interactive basic building tutorial, essentially.

Uses prim examples, notecards, and images to get ideas across, and does it very well in my opinion.

Thanks, Keira. The Ivory Tower is a great place -- worth exploring many times. Like most people, I guess I use a small subset of building skills for most things and forget about ones that I haven't needed for a while. That's why I'm always grateful for discussions in this forum and for the careful responses that people like Chosen often give -- and for reminders like yours.