DesignScript

[#1]

My first attempt in DesignScript. 

import("ProtoGeometry.dll");
import("Math.dll");

num_pts = 100;

s = 20;
t = 0..360..#num_pts;
R = 100;

x = (R + s * (Math.Cos(t / 2))) * (Math.Cos(t));
y = (R + s * (Math.Cos(t / 2))) * (Math.Sin(t));
z = s * Math.Sin(t / 2);

p1 = Point.ByCoordinates(x, y, z);

int_curve = BSplineCurve.ByControlVertices(p1,1);
int_curve.Color = Color.ByARGB(255, 0, 0, 255);

s2 = -20;
t2 = t;
R2 = R;

x2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Cos(t2));
y2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Sin(t2));
z2 = s2 * Math.Sin(t2 / 2);

p2 = Point.ByCoordinates(x2, y2, z2);
//x = print(x,y,z);

int_curve2 = BSplineCurve.ByControlVertices(p2,1);
int_curve2.Color = Color.ByARGB(255, 0, 255, 0);

l[1..num_pts] = Line.ByStartPointEndPoint(p1, p2);

loft = Surface.LoftFromCrossSections({ l[1..(num_pts-1)] });

http://inventorfaq.blogspot.de/2012/10/mobius-band-mit-autodesk-design-script.html

Juergen

http://inventorfaq.blogspot.de/

[#2 · Accepted solution]

Dear Jurgen,

This is really great to see

If I might make a few suggestions?

We can adjust this line

>l[1..num_pts] = Line.ByStartPointEndPoint(p1, p2);

to be

l = Line.ByStartPointEndPoint(p1, p2);

and designScript will just turn l into a collection automatically. This also means that we can avoid the 'first element is null' problem

and then the next line becomes:

loft = Surface.LoftFromCrossSections({ l[0..num_pts - 2], l[1..num_pts - 1] });

Which is a list of things to loft from -> to. It seems perhaps the arguments of this method could do with a bit more explaining?

But - this gives the complete script as:

//=====

import("ProtoGeometry.dll");
import("Math.dll");
num_pts = 100;
s = 20;
t = 0..360..#num_pts;
R = 100;

x = (R + s * (Math.Cos(t / 2))) * (Math.Cos(t));
y = (R + s * (Math.Cos(t / 2))) * (Math.Sin(t));
z = s * Math.Sin(t / 2);
p1 = Point.ByCoordinates(x, y, z);
int_curve = BSplineCurve.ByControlVertices(p1,1);
int_curve.Color = Color.ByARGB(255, 0, 0, 255);

s2 = -20;
t2 = t;
R2 = R;

x2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Cos(t2));
y2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Sin(t2));
z2 = s2 * Math.Sin(t2 / 2);
p2 = Point.ByCoordinates(x2, y2, z2);
//x = print(x,y,z);
int_curve2 = BSplineCurve.ByControlVertices(p2,1);
int_curve2.Color = Color.ByARGB(255, 0, 255, 0);
l = Line.ByStartPointEndPoint(p1, p2);
loft = Surface.LoftFromCrossSections({ l[0..num_pts - 2], l[1..num_pts - 1] });

//=====

Which produces a complete mobius band. Is that what you were aiming for?

On another note - I see in your blog, you say DesignScript crashes often. I'm sorry to hear that. Could you send me a screenshot? We're aware of one crashing bug, but I'd like to make sure there isn't something else we've missed.

Thanks again - this is a great start and a lovely little script

Luke

[#3]

Hi Luke,

thank you for your help to complete the script. Works great!

And because of teh crash: I get a crash after runing a script many times. Error:

but: I don't have SP1 für ACAD Mechanical 2013 installed! Will install today.

In addition to your improvement I have made this change to the script:

s2 = s * -1;

because s2 must be -s

This is my final script with your improvements:

import("ProtoGeometry.dll");
import("Math.dll");

num_pts = 100;

s = 20;
t = 0..360..#num_pts;
R = 100;

x = (R + s * (Math.Cos(t / 2))) * (Math.Cos(t));
y = (R + s * (Math.Cos(t / 2))) * (Math.Sin(t));
z = s * Math.Sin(t / 2);

p1 = Point.ByCoordinates(x, y, z);

int_curve = BSplineCurve.ByControlVertices(p1,1);
int_curve.Color = Color.ByARGB(255, 0, 0, 255);

s2 = s * -1;
t2 = t;
R2 = R;

x2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Cos(t2));
y2 = (R2 + s2 * (Math.Cos(t2 / 2))) * (Math.Sin(t2));
z2 = s2 * Math.Sin(t2 / 2);

p2 = Point.ByCoordinates(x2, y2, z2);
//x = print(x,y,z);

int_curve2 = BSplineCurve.ByControlVertices(p2,1);
int_curve2.Color = Color.ByARGB(255, 0, 255, 0);

l= Line.ByStartPointEndPoint(p1, p2);

loft = Surface.LoftFromCrossSections({ l[0..num_pts - 2], l[1..num_pts - 1] });

Thanks again!

Juergen

[#4]

Hi,

Very nice.

My 2 cts: the point collections can be computed by a single function which argument is s or -s (I removed the splines as they're not used to build the surfaces)

import("ProtoGeometry.dll");
import("Math.dll");

num_pts = 100;
s = 20;
t = 0..360..#num_pts;
R = 100;

def pts(s : double)
{
    x = (R + s * (Math.Cos(t / 2))) * (Math.Cos(t));
    y = (R + s * (Math.Cos(t / 2))) * (Math.Sin(t));
    z = s * Math.Sin(t / 2);
    return = Point.ByCoordinates(x, y, z);
}

l = Line.ByStartPointEndPoint(pts(s), pts(-s));
loft = Surface.LoftFromCrossSections({ l[0..num_pts - 2], l[1..num_pts - 1] });

[#5]

because of the crash: When I shade the drawing und run the script again (1-2 times) I get the system error.

Same problem after applying SP1 for AutoCAD Mechanical 2013.

[#6 · Accepted solution]

Sorry to know that you are facing some crash while running design script. A new update (version 0.3.24.5026) for DesignScript is available, hopefully this update fixes your crash issue. 

[#7]

NICE WORK!

THANK YOU FOR SHARING!

[#8]

Playing with this in .NET at TheSwamp, it looks like we (kaefer and I) found a way to create a single closed entity (Solid3d)

import("ProtoGeometry.dll");
import("Math.dll");

numPts = 60;
halfWid = 20;
angle = 0..360..#numPts;
radius = 100;
width = 2;

def pts(halfWid : double)
{
    x = (radius + halfWid * (Math.Cos(angle / 2))) * (Math.Cos(angle));
	y = (radius + halfWid * (Math.Cos(angle / 2))) * (Math.Sin(angle));
	z = halfWid * Math.Sin(angle / 2);
	return = Point.ByCoordinates(x, y, z);
}

lines = Line.ByStartPointEndPoint(pts(halfWid), pts(-halfWid));
lines.SetVisibility(false);
surfs = Surface.LoftFromCrossSections({ lines[0..numPts / 2], lines[numPts / 2..numPts] });
surfs.Visible = false;
solids = surfs.Thicken(width, true);
solid = solids[0].Union(solids[1]);

[#9]

Thanks for sharing. This is what technology previews are all about.