Hey Guys,

Wondering how to make helix/spring shapes...like the attached images? With specific number of coils, width and height dimensions too.

Thx.

Hi mat, I'd probably start by making a rectangle and type in your desired width and height for that so those are set. Then draw arcs on the ends, snap the center point of the arc onto the midpoint of the rectangle's end, snap the end points of the arc on to the corners of the rectangle. So now you have an arc on the end of your rectangle. Drag the arc by its midpoint and release it on the midpoint of the rectangle's end.

Now you can delete the rectangle, put in 2 lines connecting the arcs and you should have a lozenge created of your desired width and height like this:



If that works for getting the profile and width and height sizes that you require, then the next steps after that might be something like turn on control points for the lines and move them in a side view to form one step of a coil. The goal will be to make a path curve that you can then use Construct > Sweep to sweep a circle curve around to make the final shape.

- Michael

Here is what I did:

Make a rectangle in side view.

Fillet the corners to round over.

Trim the curve in half lengthwise. Make the top half red and the bottom have blue for sake of illustration.

In top view rotate (pivot) the red curve 15 degrees. Rotate (pivot) the blue curve, in the opposite direction by the same number of degrees. Note: You must pivot each curve by the exact same number of degrees in opposite directions, otherwise they won't line up correctly for the following steps).

Join the red & blue curves.

In top view, select the Array Tool (Dir) and pick the Offset, Count option. Click once on the lower point of the curve, and click again on the highest point of the curve. This will duplicate and stack the curves in whatever quantity you chose. Select all the curves and Join. Note: You can compress or expand the spring by selecting it in top view, and resizing the boundary box.

Draw a small circle to represent the diameter of the wire. Sweep (Freeform) the spring using the small circle as the profile.

Finally, trim the ends of the spring as desired.

Ed Ferguson

_CoilRectangular script:
http://moi3d.com/forum/index.php?webtag=MOI&msg=8657.1
- Brian
I believe that the pitch is constant, not variable for the curves...

Hi Michael,

Ah...great idea with the control points to make the coil steps. Sweep, got it.

Thx!

Hi Ed,

Thanks for the great visuals and clear explanation.

Resizing with the bounding box...so handy!

Thx!

Hi Brian,

You guys amaze me with your scripts! Tried the script...woooow. So easy, I feel like I'm cheating.

Thank you!

Hi guys,

Tried out your suggestions, worked perfectly!

Combined moving the control points to make the "step" portion with, array and sweep.

Thanks so much for your help!

Mat

And you can render with the free real time Simlab Composer Lite (Max 1920*1080)
http://www.simlab-soft.com/3d-products/simlab-composer-lite.aspx

Export from Moi in OBJ format
Have fun Sculpting Rendering!

Hi Pilou,

Thanks for the suggestion. I'll have to try it.

Using Keyshot for renderings. Keyshot doesn't like Moi for some reason...so I have to save the MOI file in Rhino....then put it into Keyshot.

Thx.

M

Hi mat, I think Keyshot may only read Rhino display information from .3dm files, so using .3dm format may not work.

But what should work is to write out from MoI using .obj format with the "Output: Quads & Triangles" option in the meshing options dialog box. Then open that .obj file in Keyshot.

- Michael

Hi Michael,

Thanks for the tip. Since I bounce between MOI and Rhino, I don't mind to save in 3dm.

I need to call Keyshot and request they update the software for MOI, ha.

Thx,

Mat

"Keyshot doesn't like Moi for some reason... "
HI,
I work with Moi and Keyshot and import directly 3dm files in it.
No need to save the file in Rhino.

Maybe this changed with some newer version of Keyshot, I can't remember the details.

- Michael

Keyshot Pro, (Version 6 or 7), will directly import NURBS files, including MoI NURBS files.
It is my limited understanding that the less expensive Keyshot HD does not import NURBs..., but does import meshes.
(I purchased V6 some time ago, but never upgraded to v7)

- Brian

Correct - I have Keyshot Pro ver 7 and it imports 3DM files from MoI directly.

My spring below:



Ed Ferguson

Hey guys,

I'm using Keyshot Pro 7.2.135.

Just tried a fresh MOI test file. No go. I get a window with a red stop sign "file.3dm did not appear to contain 3D geometry. Inside Rhino, please select View/Shade prior to saving it."

So I always have to re-save my MOI 3dm in Rhino...then open in KS.

Is there some setting somewhere in MOI or Keyshot? Sure would love to get MOI files to open in KS.

Thx,

Mat

In the Import panel > Geometry
Have you check Import Nurbs Data ?

Success!

Thanks Finema!

great !