topic cycloid in Modeling

cycloid

adbestias — Tue, 20 Nov 2007 16:31:54 GMT

hi!

i work with archicad 11 on windows vista and i need to draw a cycloid; is there a way to do it? is there any generator?

thank you...

Re: cycloid

Anonymous — Wed, 21 Nov 2007 23:08:46 GMT

Are you looking to include gravity in this or just the path that a point on a circle takes as it rolls? Either way it doesn't look like an easy task.

Re: cycloid

adbestias — Fri, 23 Nov 2007 09:50:39 GMT

hi! (i'm not sure if i understood «include gravity».)

i need to create a roof wich form is generated by a cycloid; the only way i see to do this is by creating a complex profile with the cycloid, and then the roof.

thank you!

Re: cycloid

Anonymous — Sat, 24 Nov 2007 00:15:22 GMT

This is a good start.en.wikipedia.org/wiki/Cycloid I've given it a shot but scripting this thing is above me so far. Maybe some guru with some spare time could show us the way! Doug

Re: cycloid

Anonymous — Sat, 24 Nov 2007 14:26:16 GMT

Hello,

You can create an new GDL object
and use the parametric equation of a
cycloid ?
all the best
Jean-Luc

---------3D script------------------------
R=10

ROTY 45
TUBE 4, 12, 16+32,

-----4 nodes for the rectangle---------
2.0, 0.0, 0,
0.0, 0.0, 0,
0.0, 0.4, 0,
2.0, 0.4, 0,

---------12 nodes to describe the 3d cycloid curve-------
R*(15*pi/180-sin(15)),0, R*(1-cos(15)), 0,
R*(30*pi/180-sin(30)),0, R*(1-cos(30)), 0,
R*(45*pi/180-sin(45)),0, R*(1-cos(45)), 0,
R*(60*pi/180-sin(60)),0, R*(1-cos(60)), 0,

R*(75*pi/180-sin(75)),0, R*(1-cos(75)), 0,
R*(90*pi/180-sin(90)),0, R*(1-cos(90)), 0,
R*(105*pi/180-sin(105)),0, R*(1-cos(105)), 0,
R*(120*pi/180-sin(120)),0, R*(1-cos(120)), 0,

R*(135*pi/180-sin(135)),0, R*(1-cos(135)), 0,
R*(150*pi/180-sin(150)),0, R*(1-cos(150)), 0,
R*(165*pi/180-sin(165)),0, R*(1-cos(165)), 0,
R*(180*pi/180-sin(180)),0, R*(1-cos(180)), 0

Re: cycloid

Anonymous — Sat, 24 Nov 2007 14:36:56 GMT

Who will notice the difference?!? 😉

Re: cycloid

Anonymous — Sat, 24 Nov 2007 14:53:23 GMT

Who will notice the difference?!?

I thought of that too Kliment. Just seemed too easy!

Re: cycloid

Anonymous — Sat, 24 Nov 2007 15:05:38 GMT

may be it matters to people
dealing with strength of materials ?

Re: cycloid

Anonymous — Sun, 25 Nov 2007 09:53:11 GMT

hi! (i'm not sure if i understood «include gravity».)

i need to create a roof wich form is generated by a cycloid; the only way i see to do this is by creating a complex profile with the cycloid, and then the roof.

thank you!

Create a Barrel-Vaulted Roof
Roof Tool > Barrel Vaulted > Click on Cycloid by Magic Wand

Re: cycloid

Rex Maximilian — Tue, 27 Nov 2007 06:50:40 GMT

That diagram is a work of art, Beart!

Re: cycloid

adbestias — Wed, 28 Nov 2007 11:16:17 GMT

thank you all for your time!

i managed to generate a cycloid with CCycloid 3.4.3 (http://www.cgl.uwaterloo.ca/~smann/ccycloid/) and then imported the *.dxf file into archicad; still had to use the spline though.

jean-luc regnier, thank you for the code!

Beart, i couldn't design a barrel vaulted roof with the magic wand; i'll check it out on the manual... thank you!

kliment, thank you too but can you try to mirror your half circle... and notice the difference?

Re: cycloid

Anonymous — Thu, 29 Nov 2007 05:39:26 GMT

adbestias wrote:
thank you all for your time!
...
Beart, i couldn't design a barrel vaulted roof with the magic wand; i'll check it out on the manual... thank you!
...

1.Drawing Cycloid:

Re: cycloid

Anonymous — Thu, 29 Nov 2007 05:41:32 GMT

2.Create a Barrel-Vaulted Roof

Roof Tool > Barrel Vaulted > Click on cycloid by Magic Wand

P.S. Magic Wand : Design > Outline Polygon with Magic Wand (press Space Bar)

Re: cycloid

Anonymous — Thu, 29 Nov 2007 12:30:00 GMT

kliment, thank you too but can you try to mirror your half circle... and notice the difference?

Adbestias,

apparently we can approximate a cycloid by a arc of a circle

with Radius of circle = 4 * Radius of the circle which generated your cycloid

if someone wants to demonstrate that...I don't think it is easy

I read somewhere that Galilée thought that the cycloid was the best
shape to built a bridge. I am not architect or civil engineer. So may be someone will tell me if it is true just by curiosity...
Best regards
Jean-Luc