rotate([0,90,0]) rotate_extrude(convexity=10) rotate (90) profile();

like this?

Am Mo., 1. Nov. 2021 um 13:24 Uhr schrieb Ray West raywest@raywest.com:

Is that what you want?

rotate_extrude(convexity=10) rotate(90) profile();

Note that 2d objects like squares and circles live in the plane XY. You are
allowed to rotate them in an axis other than z or translate them off the XY
plane and get a preview image. But that is misleading because render will
keep them in the XY plane despite the transforms. The rule of thumb is
never transform 2d objects off the XY plane. linear_extrude and
rotate_extrude operate on objects in the XY plane. After extrude you may
transform the shape as you want.

Em seg., 1 de nov. de 2021 às 13:24, Ray West raywest@raywest.com
escreveu:

This does not generate thousands of little squares or little disks:

Vector=[for( i = [0:7212.5]) [i5,(cos(i5)31)+31+(20100) ] ] ;  // your
formula
Poly=[for(L=[[[0,200]], Vector, [[7212.5*5,200]]], a=L) a];  // add the
end points
polygon(Poly);//echo(Poly) ; // verify the flat shape
rotate_extrude() rotate(90) polygon(Poly) ; // and there it is ?

On Mon, 1 Nov 2021 at 14:42, Ronaldo Persiano rcmpersiano@gmail.com wrote:

Yes, exactly. I tried a single rotate rotate_extrude(convexity=10)
rotate ([0,90,0]) profile();  and it gives a <WARNING: Scaling a 2D
object with 0 - removing object>

I didn't realise it would know which axis to rotate with just the single
value, so never tried the two rotates.

Thanks

On 01/11/2021 13:40, dpa wrote:

Well.. You can also use the "full" vector specification, but you need
to turn the 2D profile() by Z-axis.

rotate_extrude() rotate ([0,0,90]) profile();
which, admittedly, is a bit confusing, but it wokrs

Am Mo., 1. Nov. 2021 um 15:30 Uhr schrieb Ray West raywest@raywest.com:

On 11/1/2021 6:56 AM, Michael Möller wrote:

I don't see why you offset the base +200 in Y.

The lists can be a bit simpler.

Simplest is probably to build the whole polygon in one shot:

Poly=[
    [ 0, 0 ],
    for( i = [0:72*12.5]) [i*5, (cos(i*5)*31)+31+(20*100) ],
    [ 72*12.5*5, 0 ]
 ] ;  // your formula

but if you want to maintain the pattern of generating the curve
separately, you can use concat:

Poly=concat([[72*12.5*5, 0], [0, 0]], Vector );  // add the end points

or you could use the "each" list comprehension operator:

Poly=[
    [ 0, 0 ],
    each Vector,
    [ 72*12.5*5, 0 ]
 ] ;  // your formula

But the first lesson, that I'm kind of surprised that nobody has
explicitly mentioned, is that when you're planning to do a
rotate_extrude, you need to design your 2D model with the intended
radius in +X and the intended Z in Y.  I guess that you can put the
shape entirely in -X, but I wouldn't.

The sine wave should be drawn as x = f(y) to avoid the need for the
initial rotate.

Poly=[
    [ 0, 0 ],
    for( i = [0:72*12.5]) [ (cos(i*5)*31)+31+(20*100), i*5 ],
    [ 0, 72*12.5*5 ]
 ] ;  // your formula

rotate_extrude() polygon(Poly);

Note that I transposed the coordinates rather than rotating, so the
figure is in +X / +Y.

Thanks. All done and dusted now.  Printing as I type. The offset was to
show the sort of radius I was aiming for. I couldn't find out how to set
it up for programmatically generating the polygon, so thanks for the
explanation.

On 01/11/2021 17:47, Jordan Brown wrote: