Twist geometry?

[THREEL]

Hi Everyone!  Did a search on how to twist geometry and came up empty.  So, I was wondering if anyone had any helpful hints on a good way to accomplish this feat.  Pleas, take a look at the enclosed photo and tell me what you think.  I'm not talking about the curly Q's on the ends.  That's just using follow me on  a polygon that lies on a flat plane.  I'm talking about the twisted piece in the center.  Using follow me for the twisted iron, I've tried a couple of ideas, but I'm not getting the desired results.  Sorry about the pixelated photo, but I wanted to show a good close-up.  Thanks for your help!

BTW--I'm modeling in SU v. 8

[Urban 3D Modeling]

Hi Threel,

Good question, I am curious about other ideas too. I believe you are looking to make a twist like a drill bit. I would might try the spiral staircase approach. Another idea might be using follow me, like a spring but a modified rectangular shape. I think you may have tried this already but its in the video link below. If you're doing this for GE I might suggest using a transparent .png instead of the complex geometry that this shape will ultimately be. Let us know if you come up with something good!

http://www.youtube.com/watch?v=H1IO2f1xvd0&feature=related

Cheers, Steve

[TomHarvey]

Hi Threel,

Here's one way to do it. This took me about ten minutes

Tom

[SnowTiger]

What you are trying to make is a Helix of sorts.
Follow Me is one way but it also requires an additional Ruby that maintains the level plain for the profile to follow (whereas without the ruby script, the profile will twist out of alignment .. so to speak).
There is another Plugin/Tool that will also help with the Twist of a Group.

I hate to say it though .. it is late here and I'm wiped out tonight.
So I will promise to get back to this thread as early as I can on Sunday and hopefully provide links to the script and tools that I am referring to.

Sorry for the tease in the meantime.

[THREEL]

Thanks Tom!  I'm working on something like this, but still not quite getting the desired results.  Still at the drawing board... ;)

[THREEL]

Yep!  It's like a helix, but I'm twisting the geometry and not just following it up a helical curve around an outer radius.  I've tried a few different ways, but still not quite there, yet.  I thought I had downloaded a Ruby Script that would keep the geometry aligned with the reference curved line.  I used that script to create a better banister for a spiral stair case that I modeled.  But, for the life of me, I can't seem to find it, right now.

[Tim Shoemaker]

I did a type of twist when creating Knott's Berry Farm's Boomerang Roller Coaster (http://sketchup.google.com/3dwarehouse/details?mid=e06c82aba00b5fbb55965bdd4fd06f0) it has two regular loops, which were "easy" but the twisty part in the middle was quite a challenge.

I did this, starting with building maker to create the basic image... I added many small boxes together to get the basic shape. Then I took it to Sketchup to add in details, smooth out bumps, add the supports, etc. I would love to know an easier way, but I got this done.

[matthiasbasler]

Hi Threel,
since I don't have a plugin at hand either, I would simply do this manually. The geometry is not too complex either.
Basically it is a rectangle in top-down view that rotates around its center by 90°. So why not model it like this?

You create the bottom rectangle, then a copy of it slightly above it (1/9 of the total height of the twist.) Then you rotate the upper rectangle by 10° around its center. Now connect lower and upper rectangle's corners until they form a slightly twisted box. Remove top and bottom plate and make the whole thing a component. Now all you have to do is stack 9 of these components on top of each other (each one slightly more rotated) and you have a full 90° rotation. Now you can save the whole thing as component for re-use in other models.
This should take no longer than 5 minutes or so.

If you like you can afterwards explode the 9 inner components, and smooth out the edges of the whole twist, giving it a smoother appearance.

...BTW This would give a nice reusable DYNAMIC component with parameters {x, y, height, rotation angle} , if anyone wants to define one.

Matthias Basler

[SnowTiger]

Okay.. sorry for the delay.

The first script/plugin I was referring to last night is called "FollowMeAndKeep".   This helps keep a horizontal plain horizontal while it follows a path. Whereas without it, the plain/profile tends to get twisted out of orientation.

But more importantly is the second plugin I was referring to.
It is called "Fredo Scale".
Using Fredo Scale, you could first create a rectangular box, Group it and then use the plugin's tool called "Twisting With Orientation of Scaling Box".
This will allow you to twist the Grouped Geometry without creating fold lines.
While you twist the group, you will first see fold lines being generated, but as soon as you complete the twisting motion, the sides will smoothen, eliminating the fold lines.

For best results, you "may" wish to create a partial twist, then copy/paste this twisted block to stack them and rotate them.
Then you can explode, restitch and re-group the geometry, resulting in your twisted baluster (or whatever you are making).

Both of the above-mentioned Plugins are readily available  .. just do a quick search and download'em.

"IF" you can't find them, let me know and I'll find the links.. but recall finding both very easy the first time.

Happy Modeling

[THREEL]

Thanks Snow!  I just downloaded the Fredo Scale plug-in and extracted the files.  I'm pretty positive in the proper location.  When I opened SketchUp, I received this Error Message:  Error Loading File ZLoader__FredoScale.rb
no such file to load -- LibFredo6.rb

Not sure what's going on.  It does look like a really sweet plug-in, if I can get it to work. :-D

[THREEL]

Thanks Matthias!  This worked, but I did it a little the hard way.  I just drew and arrayed a flat plane.  Then I rotated them 10 deg. further than the lower one.  After that, it was just connecting end points with lines to get triangles, but you do need to make sure both sides are triangulated in the same direction.  I was getting bleed through, when they were triangulated in opposite directions.  Is there any way to copy at an offset distance and rotate the copies all in one shot?  This would be really easy, if that can be done.

[SnowTiger]

Hello again THREEL

I'm sorry to hear the file didn't load properly.
I don't recall but there may be an additional plugin/ruby that is required to make Fredo Scale work properly (as is the case with several other plugins).
Where there no installation instructions with the FS file ?

Mine is installed in the SU Plugins folder (no sub folders).

I'll look into it to see if I can't find a solution for you.
Until then, best wishes to you.

[SnowTiger]

PS>
Have you seen and read this page ?
It has installation instructions as well as a link to a PDF Manual for using Fredo Scale 2.   
There is a file update dated Jan 2011 to version 2.1a

If I read correctly, it appears you will need at least one of the following other plugins for FS to work (as indicated at the following page SketchUcation under the OVERVIEW PURPOSE Heading).

• FredoScale
• Tools on Surface
• RoundCorner
• Curviloft
• HoverSelect
• GhostComp

I hope this isn't just getting confusing. But I do recommend reading ALL associated articles that follow the FS topic at SketchUcation.
Best of Luck.
SnowTiger

[THREEL]

Thanks Snow!  Here's what I was missing: LibFredo6 3.6  Once you get the hang of it, this looks like a great plug-in.  I, also downloaded RoundCorner & Curviloft.  These are all wonderful additions to the Tool Set! :)