Back in the day (1992 - yikes!) I wrote programs that started with an
icosahedron and recursively divided each triangular face into four
subtriangles and so on to lay a close to regular mesh over a sphere to
arbitrary resolution. [The I solved simple pdes using a finite element
method, but I digres
Maybe I should've included an example. If points->surface was a function that
took a list of points and connected those points into a surface (like in my
last email), then this code would draw a sphere at the origin with a radius of
1:
(define (point-on-sphere ctr r theta phi)
(let* ([z (* r
Is there something that can take a list of points, (or maybe a list of lists of
points) and connects those points into a surface, sort of like lines3d takes a
list of points and connects them into a curve? And then define
parametric-surface3d could be defined in terms of it, like parametric3d i
> It might be time to take another look at Jens Axel's ideas for adaptive
> sampling, now that Plot can do it in 3D without b0rking it.
In a nut shell: A plotting algorithm should sample the function the
same way a numeric integration routine does. The number of samples in
a given interval should
Plot doesn't have parametric 3D surfaces yet because they can contain
arbitrarily large, arbitrarily close, or intersecting polygons. Plot's
current 3D engine sorts polygons wrongly when they're not in a grid or
are too close together, and it never draws intersecting polygons right.
The upcomi
Is there something for plotting 3D parametric surfaces? (where there are two
parameters instead of one)
If there is, then I would do something like this:
(define (sphere3d ctr-x ctr-y ctr-z r #:color color)
(parametric-surface3D (lambda (theta phi) ; theta and phi are the parameters
On 04/11/2014 02:04 AM, Konrad Hinsen wrote:
Neil Toronto writes:
> On git HEAD this takes about 15-20 seconds on my computer, depending on
> random sphere placement and size. It takes 5-6 seconds for 81 samples
> instead of 121. For comparison, the following takes 7-10 seconds with
> 12
Neil Toronto writes:
> On git HEAD this takes about 15-20 seconds on my computer, depending on
> random sphere placement and size. It takes 5-6 seconds for 81 samples
> instead of 121. For comparison, the following takes 7-10 seconds with
> 121 samples and 3-4 seconds with 81 samples.
Than
On 04/10/2014 08:16 PM, Konrad Hinsen wrote:
Neil Toronto writes:
> It's unfortunately not. But I think there's something you can do
> instead: use `parametric-interval' to draw the circles instead.
Thanks for the example, which contains some nice tricks I'll keep in
mind for some other app
Neil Toronto writes:
> It's unfortunately not. But I think there's something you can do
> instead: use `parametric-interval' to draw the circles instead.
Thanks for the example, which contains some nice tricks I'll keep in
mind for some other application. But I don't see a way to use this for
On 04/10/2014 08:17 AM, Konrad Hinsen wrote:
Hi everyone,
I am trying to use (abuse?) Racket's 3D plots for molecular
visualization. It actually works out better than I expected, except
that I haven't yet figured out how to control the size of the plot
symbols in the way I want.
The documentat
Hi everyone,
I am trying to use (abuse?) Racket's 3D plots for molecular
visualization. It actually works out better than I expected, except
that I haven't yet figured out how to control the size of the plot
symbols in the way I want.
The documentation says no more than that the size of a symbol
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