Super ellipsoid
Sorry guys to open the theme again, but I can't reply to it, as I wasn't
on the list when it was posted and found the thread on the Empathy web
mirror ...
So, here is my compact code for the super ellipsoid. I used a tricky
hull to display the output. However this obviously only works for convex
shapes i.e. nx, ny, nz values >= 1
points = Superellipse(a=10, b=20, c=30, nx=2, ny=2, nz=2, step=3);
// draw point cloud (hull() works for convex shapes only)
hull() polyhedron(points, [[for(i=[0:len(points)-1]) i]]);
function Superellipse(a=1, b=1, c=1, nx=2, ny=2, nz=2, step=10) =
[ for(u=[-90:step:90], v=[0:step:360])
let(x = a*sign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(cos(v))pow(abs(cos(v)),2/ny))
let(y = bsign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(sin(v))pow(abs(sin(v)),2/ny))
let(z = csign(sin(u)) *pow(abs(sin(u)),2/nz))
[x,y,z]
];
I think it's been quite a long time since that hack was discussed here.
One discovery from the last time around is that it's faster (I think
possibly a lot faster) to divide your points into triangles rather than
passing one huge "face". Maybe it triangulates the face? This hack is in
BOSL2 as hull_points().
On Fri, Feb 14, 2025 at 5:52 PM Rudolf via Discuss <
discuss@lists.openscad.org> wrote:
Sorry guys to open the theme again, but I can't reply to it, as I wasn't
on the list when it was posted and found the thread on the Empathy web
mirror ...
So, here is my compact code for the super ellipsoid. I used a tricky hull
to display the output. However this obviously only works for convex shapes
i.e. nx, ny, nz values >= 1
points = Superellipse(a=10, b=20, c=30, nx=2, ny=2, nz=2, step=3);
// draw point cloud (hull() works for convex shapes only)
hull() polyhedron(points, [[for(i=[0:len(points)-1]) i]]);
function Superellipse(a=1, b=1, c=1, nx=2, ny=2, nz=2, step=10) =
[ for(u=[-90:step:90], v=[0:step:360])
let(x = a*sign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(cos(v))pow(abs(cos(v)),2/ny))
let(y = bsign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(sin(v))pow(abs(sin(v)),2/ny))
let(z = csign(sin(u)) *pow(abs(sin(u)),2/nz))
[x,y,z]
];
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The original mail was not a super ellipsoid.
It was made by the use of bspline curves if I remember correctly.
On Sat, 15 Feb, 2025, 4:21 am Rudolf via Discuss, <
discuss@lists.openscad.org> wrote:
Sorry guys to open the theme again, but I can't reply to it, as I wasn't
on the list when it was posted and found the thread on the Empathy web
mirror ...
So, here is my compact code for the super ellipsoid. I used a tricky hull
to display the output. However this obviously only works for convex shapes
i.e. nx, ny, nz values >= 1
points = Superellipse(a=10, b=20, c=30, nx=2, ny=2, nz=2, step=3);
// draw point cloud (hull() works for convex shapes only)
hull() polyhedron(points, [[for(i=[0:len(points)-1]) i]]);
function Superellipse(a=1, b=1, c=1, nx=2, ny=2, nz=2, step=10) =
[ for(u=[-90:step:90], v=[0:step:360])
let(x = a*sign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(cos(v))pow(abs(cos(v)),2/ny))
let(y = bsign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(sin(v))pow(abs(sin(v)),2/ny))
let(z = csign(sin(u)) *pow(abs(sin(u)),2/nz))
[x,y,z]
];
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sorry, please ignore, I pasted some other message it seems.
On Sat, 15 Feb 2025 at 07:21, Sanjeev Prabhakar sprabhakar2006@gmail.com
wrote:
The original mail was not a super ellipsoid.
It was made by the use of bspline curves if I remember correctly.
On Sat, 15 Feb, 2025, 4:21 am Rudolf via Discuss, <
discuss@lists.openscad.org> wrote:
Sorry guys to open the theme again, but I can't reply to it, as I wasn't
on the list when it was posted and found the thread on the Empathy web
mirror ...
So, here is my compact code for the super ellipsoid. I used a tricky hull
to display the output. However this obviously only works for convex shapes
i.e. nx, ny, nz values >= 1
points = Superellipse(a=10, b=20, c=30, nx=2, ny=2, nz=2, step=3);
// draw point cloud (hull() works for convex shapes only)
hull() polyhedron(points, [[for(i=[0:len(points)-1]) i]]);
function Superellipse(a=1, b=1, c=1, nx=2, ny=2, nz=2, step=10) =
[ for(u=[-90:step:90], v=[0:step:360])
let(x = a*sign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(cos(v))pow(abs(cos(v)),2/ny))
let(y = bsign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(sin(v))pow(abs(sin(v)),2/ny))
let(z = csign(sin(u)) *pow(abs(sin(u)),2/nz))
[x,y,z]
];
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To unsubscribe send an email to discuss-leave@lists.openscad.org
original shape posted was this:
[image: Screenshot 2025-01-27 at 9.35.07 PM.png]
On Sat, 15 Feb 2025 at 07:25, Sanjeev Prabhakar sprabhakar2006@gmail.com
wrote:
sorry, please ignore, I pasted some other message it seems.
On Sat, 15 Feb 2025 at 07:21, Sanjeev Prabhakar sprabhakar2006@gmail.com
wrote:
The original mail was not a super ellipsoid.
It was made by the use of bspline curves if I remember correctly.
On Sat, 15 Feb, 2025, 4:21 am Rudolf via Discuss, <
discuss@lists.openscad.org> wrote:
Sorry guys to open the theme again, but I can't reply to it, as I wasn't
on the list when it was posted and found the thread on the Empathy web
mirror ...
So, here is my compact code for the super ellipsoid. I used a tricky
hull to display the output. However this obviously only works for convex
shapes i.e. nx, ny, nz values >= 1
points = Superellipse(a=10, b=20, c=30, nx=2, ny=2, nz=2, step=3);
// draw point cloud (hull() works for convex shapes only)
hull() polyhedron(points, [[for(i=[0:len(points)-1]) i]]);
function Superellipse(a=1, b=1, c=1, nx=2, ny=2, nz=2, step=10) =
[ for(u=[-90:step:90], v=[0:step:360])
let(x = a*sign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(cos(v))pow(abs(cos(v)),2/ny))
let(y = bsign(cos(u)) *pow(abs(cos(u)),2/nx) *
sign(sin(v))pow(abs(sin(v)),2/ny))
let(z = csign(sin(u)) *pow(abs(sin(u)),2/nz))
[x,y,z]
];
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To unsubscribe send an email to discuss-leave@lists.openscad.org
Hello,
I'm wondering, is there a way to test in Openscad an array for the
existence of a value?
e.g.
modus=[0,2,4,6]; // this is the array
var=3; // this my set value
if (var @ modus) then ... (@ stands for the unknown operator in my example)
I scanned through the wiki but couldn't find the answer.
Thanks in advance.
fred
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/List_Comprehensions
There are similar examples in the documentation.
Dan
On Sat, Feb 15, 2025 at 4:29 PM FPA via Discuss discuss@lists.openscad.org
wrote:
Hello,
I'm wondering, is there a way to test in Openscad an array for the
existence of a value?
e.g.
modus=[0,2,4,6]; // this is the array
var=3; // this my set value
if (var @ modus) then ... (@ stands for the unknown operator in my
example)
I scanned through the wiki but couldn't find the answer.
Thanks in advance.
fred
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To unsubscribe send an email to discuss-leave@lists.openscad.org
I think what he's looking for is the search function. So something like
search([var], modus). Note, the syntax and behavior of search is bizarre.
On Sat, Feb 15, 2025 at 11:37 AM Dan Perry via Discuss <
discuss@lists.openscad.org> wrote:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/List_Comprehensions
There are similar examples in the documentation.
Dan
On Sat, Feb 15, 2025 at 4:29 PM FPA via Discuss <
discuss@lists.openscad.org> wrote:
Hello,
I'm wondering, is there a way to test in Openscad an array for the
existence of a value?
e.g.
modus=[0,2,4,6]; // this is the array
var=3; // this my set value
if (var @ modus) then ... (@ stands for the unknown operator in my
example)
I scanned through the wiki but couldn't find the answer.
Thanks in advance.
fred
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
On Feb 15, 2025, at 8:29 AM, FPA via Discuss discuss@lists.openscad.org wrote:
I'm wondering, is there a way to test in Openscad an array for the
existence of a value?
BOSL2 has a fairly optimized in_list() implementation that gets around the oddities of search(), while taking advantage of its speed. Here’s a de-BOSL2’ed version of the code it uses:
// Function: in_list()
// Synopsis: Returns true if a value is in a list.
// Topics: List Handling
// See Also: select(), slice()
// Usage:
// bool = in_list(val, list, [idx]);
// Description:
// Returns true if value val is in list list. When val==NAN the answer will be false for any list.
// Arguments:
// val = The simple value to search for.
// list = The list to search.
// idx = If given, searches the given columns for matches for val.
// Example:
// a = in_list("bar", ["foo", "bar", "baz"]); // Returns true.
// b = in_list("bee", ["foo", "bar", "baz"]); // Returns false.
// c = in_list("bar", [[2,"foo"], [4,"bar"], [3,"baz"]], idx=1); // Returns true.
// Note that a huge complication occurs because OpenSCAD's search() finds
// index i as a hits if the val equals list[i] but also if val equals list[i][0].
// This means every hit needs to be checked to see if it's actually a hit,
// and if the first hit is a mismatch we have to keep searching.
// We assume that the normal case doesn't have mixed data, and try first
// with just one hit, but if this finds a mismatch then we try again
// with all hits, which could be slow for long lists.
function in_list(val,list,idx) =
assert(is_list(list),"Input is not a list")
assert(is_undef(idx) || is_num(idx), "Invalid idx value.")
let( firsthit = search([val], list, num_returns_per_match=1, index_col_num=idx)[0] )
firsthit==[] ? false
: is_undef(idx) && val==list[firsthit] ? true
: !is_undef(idx) && val==list[firsthit][idx] ? true
// first hit was found but didn't match, so try again with all hits
: let ( allhits = search([val], list, 0, idx)[0])
is_undef(idx) ? [for(hit=allhits) if (list[hit]==val) 1] != []
: [for(hit=allhits) if (list[hit][idx]==val) 1] != [];
- Revar
Adrian Mariano wrote:
I think what he's looking for is the search function. So something like
search([var], modus). Note, the syntax and behavior of search is bizarre.
On Sat, Feb 15, 2025 at 11:37 AM Dan Perry via Discuss <
discuss@lists.openscad.org> wrote:
https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/List_Comprehensions
There are similar examples in the documentation.
Dan
On Sat, Feb 15, 2025 at 4:29 PM FPA via Discuss <
discuss@lists.openscad.org> wrote:
Hello,
I'm wondering, is there a way to test in Openscad an array for the
existence of a value?
e.g.
modus=[0,2,4,6]; // this is the array
var=3; // this my set value
if (var @ modus) then ... (@ stands for the unknown operator in my
example)
I scanned through the wiki but couldn't find the answer.
Thanks in advance.
fred
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
I came up with the following solution
list1=[0,1,2];
modus=2;
result=len(search(modus, list1));
echo(result);
if (result>0) {
echo("result is ", result);
}
else {
echo("there is nothing");
};
// or ...
if (len(search(modus, list1))) {
echo ("modus " , modus, "is detected");
};
Btw. This thread never showed up my email client. Any explanation why that could be?