Tag Shading (3D) -- Asymptote Gallery

🔗Asymptote Gallery Tagged by “Shading (3D)” #161

🔗graph3-fig011

Figure graph3 011 Generated with Asymptote

import graph3;
import palette;
import contour;
size(14cm,0);
currentprojection=orthographic(-1,-1.5,0.75);
currentlight=(-1,0,5);

real a=1, b=1;
real f(pair z) { return a*(6+sin(z.x/b)+sin(z.y/b));}
real g(pair z){return f(z)-6a;}

// The axes
limits((0,0,4a),(14,14,8a));
xaxis3(Label("$x$",MidPoint),OutTicks());
yaxis3(Label("$y$",MidPoint),OutTicks(Step=2));
ticklabel relativelabel()
{
  return new string(real x) {return (string)(x-6a);};
}
zaxis3(Label("$z$",Relative(1),align=2E),Bounds(Min,Max),OutTicks(relativelabel()));

// The surface
surface s=surface(f,(0,0),(14,14),100,Spline);

pen[] pens=mean(palette(s.map(zpart),Gradient(yellow,red)));

// Draw the surface
draw(s,pens);
// Project the surface onto the XY plane.
draw(planeproject(unitsquare3)*s,pens,nolight);

// Draw contour for "datumz"
real[] datumz={-1.5, -1, 0, 1, 1.5};
guide[][] pl=contour(g,(0,0),(14,14),datumz);
for (int i=0; i < pl.length; ++i)
  for (int j=0; j < pl[i].length; ++j)
    draw(path3(pl[i][j]));

// Draw the contours on the surface
draw(lift(f,pl));

if(!is3D())
  shipout(bbox(3mm,Fill(black)));

🔗graph3-fig012

Figure graph3 012 Generated with Asymptote

import graph3;
import palette;

real sinc(real x){return x != 0 ? sin(x)/x : 1;}

real f(pair z){
  real value = (sinc(pi*z.x)*sinc(pi*z.y))**2;
  return value^0.25;
}

currentprojection=orthographic(0,0,1);

size(10cm,0);

surface s=surface(f,(-5,-5),(5,5),100,Spline);
s.colors(palette(s.map(zpart),Gradient((int)2^11 ... new pen[]{black,white})));

draw(planeproject(unitsquare3)*s,nolight);

🔗graph3-fig013

Figure graph3 013 Generated with Asymptote

From TeXgraph exemples.

Show graph3/fig0130.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Graph3.asy
Tags : #Graph (3D) | #Palette | #Surface | #Shading (3D)

settings.render=0;
import graph3;
import palette;
size(10cm,0);
currentprojection=orthographic(2,-2,2.5);

real f(pair z) {
  real u=z.x, v=z.y;
  return (u/2+v)/(2+cos(u/2)*sin(v));
}

surface s=surface(f,(0,0),(14,14),150,Spline);
draw(s,mean(palette(s.map(zpart),Gradient(yellow,red))));

if(!is3D())
  shipout(bbox(3mm,Fill(black)));

🔗graph3-fig014

Figure graph3 014 Generated with Asymptote

From TeXgraph exemples.

Show graph3/fig0140.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Graph3.asy
Tags : #Graph (3D) | #Palette | #Surface | #Shading (3D)

settings.render=0;
import graph3;
import palette;
size(15cm,0);
currentprojection=orthographic(2,-2,2.5);

real f(pair z) {
  real u=z.x, v=z.y;
  return (u/2+v)/(2+cos(u/2)*sin(v));
}

surface s=surface(f,(0,0),(14,14),50,Spline);
s.colors(palette(s.map(zpart),Gradient(yellow,red)));

draw(s);

if(!is3D())
  shipout(bbox(3mm,Fill(black)));

🔗graph3-fig015

Figure graph3 015 Generated with Asymptote

settings.render=0;
import graph3;
size(15cm);

currentprojection=orthographic(4,2,4);

real r(real Theta, real Phi){return 1+0.5*(sin(2*Theta)*sin(2*Phi))^2;}
triple f(pair z) {return r(z.x,z.y)*expi(z.x,z.y);}

pen[] pens(triple[] z)
{
  return sequence(new pen(int i) {
      real a=abs(z[i]);
      return a < 1+1e-3 ? black : interp(blue, red, 2*(a-1));
    },z.length);
}

surface s=surface(f,(0,0),(pi,2pi),100,Spline);
// Interpolate the corners, and coloring each patch with one color
// produce some artefacts
draw(s,pens(s.cornermean()));

if(!is3D())
  shipout(bbox(3mm,Fill(black)));

🔗graph3-fig016

Figure graph3 016 Generated with Asymptote

settings.render=0;
import graph3;
size(15cm);

currentprojection=orthographic(4,2,4);

real r(real Theta, real Phi){return 1+0.5*(sin(2*Theta)*sin(2*Phi))^2;}
triple f(pair z) {return r(z.x,z.y)*expi(z.x,z.y);}

pen[][] pens(triple[][] z)
{
  pen[][] p=new pen[z.length][];
  for(int i=0; i < z.length; ++i) {
    triple[] zi=z[i];
    p[i]=sequence(new pen(int j) {
	real a=abs(zi[j]);
	return a < 1+1e-3 ? black : interp(blue, red, 2*(a-1));},
      zi.length);
  }
  return p;
}

surface s=surface(f,(0,0),(pi,2pi),100,Spline);
// Here we interpolate the pens, this looks smoother, with fewer artifacts
draw(s,mean(pens(s.corners())));

if(!is3D())
  shipout(bbox(3mm,Fill(black)));

🔗graph3-fig017

Figure graph3 017 Generated with Asymptote

import graph3;
size(16cm, 0);

currentprojection=orthographic(4, 2, 4);

real r(real Theta, real Phi){return 1+0.5*(sin(2*Theta)*sin(2*Phi))^2;}
triple f(pair z) {return r(z.x, z.y)*expi(z.x, z.y);}

pen[][] pens(triple[][] z)
{
  pen[][] p=new pen[z.length][];
  for(int i=0; i < z.length; ++i) {
    triple[] zi=z[i];
    p[i]=sequence(new pen(int j) {
    real a=abs(zi[j]);

    return a < 1+1e-3 ? black : interp(blue, red, 2*(a-1));}, zi.length);
  }

  return p;
}

surface s=surface(f, (0, 0), (pi, 2pi), 100, Spline);
// Here we determine the colors of vertexes (vertex shading).
// Since the PRC output format does not support vertex shading of Bezier surfaces, PRC patches
// are shaded with the mean of the four vertex colors.
s.colors(pens(s.corners()));
draw(s);

if(!is3D())
  shipout(bbox(1mm, Fill(black)));

🔗graph3-fig018

Figure graph3 018 Generated with Asymptote

The spherical harmonics $Y_l^m(\theta,\varphi)$ are the angular portion of the solution to Laplace's equation in spherical coordinates where azimuthal symmetry is not present.

The spherical harmonics are defined by:

Y_l^m(\theta,\varphi)=\sqrt{\frac{2l+1}{4\pi}\frac{(l-m)!}{(l+m)!}}P_{l}^{m}(\cos\theta)e^{im\varphi}

where $m=-l,\,-(l-1),\,\ldots,\,0,\,\ldots,\,l-1,\,l$ and $P_l^m$ is the Legendre polynomial.

Source

import palette;
import math;
import graph3;

typedef real fct(real);
typedef pair zfct2(real,real);
typedef real fct2(real,real);

real binomial(real n, real k)
{
  return gamma(n+1)/(gamma(n-k+1)*gamma(k+1));
}

real factorial(real n) {
  return gamma(n+1);
}

real[] pdiff(real[] p)
{ // p(x)=p[0]+p[1]x+...p[n]x^n
  // retourne la dérivée de p
  real[] dif;
  for (int i : p.keys) {
    if(i != 0) dif.push(i*p[i]);
  }
  return dif;
}

real[] pdiff(real[] p, int n)
{ // p(x)=p[0]+p[1]x+...p[n]x^n
  // dérivée n-ième de p
  real[] dif={0};
  if(n >= p.length) return dif;
  dif=p;
  for (int i=0; i < n; ++i)
    dif=pdiff(dif);
  return dif;
}

fct operator *(real y, fct f)
{
  return new real(real x){return y*f(x);};
}

zfct2 operator +(zfct2 f, zfct2 g)
{// Défini f+g
  return new pair(real t, real p){return f(t,p)+g(t,p);};
}

zfct2 operator -(zfct2 f, zfct2 g)
{// Défini f-g
  return new pair(real t, real p){return f(t,p)-g(t,p);};
}

zfct2 operator /(zfct2 f, real x)
{// Défini f/x
  return new pair(real t, real p){return f(t,p)/x;};
}

zfct2 operator *(real x,zfct2 f)
{// Défini x*f
  return new pair(real t, real p){return x*f(t,p);};
}

fct fct(real[] p)
{ // convertit le tableau des coefs du poly p en fonction polynôme
  return new real(real x){
    real y=0;
    for (int i : p.keys) {
      y += p[i]*x^i;
    }
    return y;
  };
}

real C(int l, int m)
{
  if(m < 0) return 1/C(l,-m);
  real OC=1;
  int d=l-m, s=l+m;
  for (int i=d+1; i <=s ; ++i) OC *= i;
  return 1/OC;
}

int csphase=-1;
fct P(int l, int m)
{ // Polynôme de Legendre associé
  // http://mathworld.wolfram.com/LegendrePolynomial.html
  if(m < 0) return (-1)^(-m)*C(l,-m)*P(l,-m);
  real[] xl2;
  for (int k=0; k <= l; ++k) {
    xl2.push((-1)^(l-k)*binomial(l,k));
    if(k != l) xl2.push(0);
  }
  fct dxl2=fct(pdiff(xl2,l+m));
  return new real(real x){
    return (csphase)^m/(2^l*factorial(l))*(1-x^2)^(m/2)*dxl2(x);
  };
}

zfct2 Y(int l, int m)
{// http://fr.wikipedia.org/wiki/Harmonique_sph%C3%A9rique#Expression_des_harmoniques_sph.C3.A9riques_normalis.C3.A9es
  return new pair(real theta, real phi) {
    return sqrt((2*l+1)*C(l,m)/(4*pi))*P(l,m)(cos(theta))*expi(m*phi);
  };
}

real xyabs(triple z){return abs(xypart(z));}

size(16cm);
currentprojection=orthographic(0,1,1);

zfct2 Ylm;

triple F(pair z)
{
  //   real r=0.75+dot(0.25*I,Ylm(z.x,z.y));
  //   return r*expi(z.x,z.y);
  real r=abs(Ylm(z.x,z.y))^2;
  return r*expi(z.x,z.y);
}

int nb=4;
for (int l=0; l < nb; ++l) {
  for (int m=0; m <= l; ++m) {
    Ylm=Y(l,m);

    surface s=surface(F,(0,0),(pi,2pi),60);
    s.colors(palette(s.map(xyabs),Rainbow()));

    triple v=(-m,0,-l);
    draw(shift(v)*s);
    label("$Y_"+ string(l) + "^" + string(m) + "$:",shift(X/3)*v);
  }
}

🔗solids-fig008

Figure solids 008 Generated with Asymptote

import solids;
import palette;
size(14cm,0);
currentlight=light(
  gray(0.4),
  specularfactor=3,
  (-0.5,-0.25,0.45),
  (0.5,-0.5,0.5),(0.5,0.5,0.75)
);

nslice=4*nslice;
surface s=surface(sphere(O,1));
draw(s,lightgrey);

path3 pl=plane((1,0,0),(0,1,0),(0,0,-1));
surface pls=shift(3,3,-1e-3)*scale(-6,-6,1)*surface(pl);
draw(pls,0.7*red);

real dist(triple z){return abs(z-Z);}

surface shade;
for (int i=0; i < currentlight.position.length; ++i) {
  shade=planeproject(pl,currentlight.position[i])*s;
  draw(shade,mean(palette((shade.map(dist)),
                          Gradient(black,gray(0.6)))),
       nolight);
}

🔗three-fig002

Figure three 002 Generated with Asymptote

import three;
import palette;

size(12cm);
currentprojection=orthographic(1,1,1.5);
currentlight=(1,0,1);

triple P00=-X-Y+0.5*Z, P03=-X+Y, P33=X+Y, P30=X-Y;

triple[][] P={
  {P00,P00+(-0.5,0.5,-1),P03+(0,-0.5,1),P03},
  {P00+(0.5,-0.5,-1),(-0.5,-0.5,0.5),(-0.5,0.5,-1.5),P03+(0.5,0,1)},
  {P30+(-0.5,0,1),(0.5,-0.5,-1.5),(0.5,0.5,1),P33+(-0.5,0,1)},
  {P30,P30+(0,0.5,1),P33+(0,-0.5,1),P33}
};

surface s=surface(patch(P));
s.colors(palette(s.map(zpart),Gradient(yellow,red)));
// s.colors(palette(s.map(zpart),Rainbow()));

draw(s);
draw(sequence(new path3(int i){
      return s.s[i].external();},s.s.length), bp+orange);


if(!is3D())
  shipout(bbox(Fill(lightgrey)));

🔗three-fig003

Figure three 003 Generated with Asymptote

import three;

size(10cm);
currentlight=(0,0,1);

surface sf=surface(patch(P=new triple[][] {
      {(0,0,0),(1,0,0),(1,0,0),(2,0,0)},
      {(0,1,0),(1,0,1),(1,0,1),(2,1,0)},
      {(0,1,0),(1,0,-1),(1,0,-1),(2,1,0)},
      {(0,2,0),(1,2,0),(1,2,0),(2,2,0)}
    }));

draw(sf,surfacepen=yellow);
draw(sf.s[0].vequals(0.5),squarecap+2bp+blue,currentlight);
draw(sf.s[0].uequals(0.5),squarecap+2bp+red,currentlight);

🔗tube-fig005

Figure tube 005 Generated with Asymptote

Show tube/fig0050.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Graph (3D) | #Shading (3D)

import tube;
import graph3;

size(10cm,0);
currentprojection=perspective(4,3,4);
real x(real t) {return (1/sqrt(1+0.5*t^2))*cos(2pi*t);}
real y(real t) {return (1/sqrt(1+0.5*t^2))*sin(2pi*t);}
real z(real t) {return t;}

path3 p=graph(x,y,z,0,2.7,operator ..);
path section=scale(0.2)*polygon(5);

// tube.asy defines a "colored path".
// The value of coloredtype may be coloredSegments or coloredNodes.
// Here the path scale(0.2)*polygon(5) has fixed colored SEGMENTS.
coloredpath cp=coloredpath(section,
                           // The array of pens become automatically cyclic.
                           new pen[]{0.8*red, 0.8*blue, 0.8*yellow, 0.8*purple, black},
                           colortype=coloredSegments);

// Draw the tube, each SEGMENT of the section is colored.
draw(tube(p,cp));

🔗tube-fig006

Figure tube 006 Generated with Asymptote

Show tube/fig0060.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Graph (3D) | #Shading (3D)

import tube;
import graph3;

size(10cm,0);
currentprojection=perspective(4,3,4);
real x(real t) {return (1/sqrt(1+0.5*t^2))*cos(2pi*t);}
real y(real t) {return (1/sqrt(1+0.5*t^2))*sin(2pi*t);}
real z(real t) {return t;}

path3 p=graph(x,y,z,0,2.7,operator ..);
path section=scale(0.2)*polygon(5);

// Here the path scale(0.2)*polygon(5) has colored NODES.
coloredpath cp=coloredpath(section,
                           new pen[]{0.8*red, 0.8*blue, 0.8*yellow, 0.8*purple, black},
                           colortype=coloredNodes);

// Draw the tube, each NODE of the section is colored.
draw(tube(p,cp));

🔗tube-fig007

Figure tube 007 Generated with Asymptote

Show tube/fig0070.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Graph (3D) | #Shading (3D)

import tube;
import graph3;

size(10cm,0);
currentprojection=perspective(4,3,4);
real x(real t) {return (1/sqrt(1+0.5*t^2))*cos(2pi*t);}
real y(real t) {return (1/sqrt(1+0.5*t^2))*sin(2pi*t);}
real z(real t) {return t;}

path3 p=graph(x,y,z,0,2.7,operator ..);
path section=scale(0.2)*polygon(5);

// Define a pen wich depends of a real t. t represent the "reltime" of the path3 p.
pen pen(real t){
  return interp(red,blue,1-2*abs(t-0.5));
}

// Here the section has colored segments (by default) depending to reltime.
draw(tube(p,coloredpath(section,pen)));

🔗tube-fig008

Figure tube 008 Generated with Asymptote

Show tube/fig0080.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Graph (3D) | #Shading (3D)

import tube;
import graph3;
size(12cm,0);
currentprojection=perspective((-1,1,1));

int p=7, q=3;
real n=p/q;
real a=1, b=1;
real x(real t){return a*cos(t);}
real y(real t){return a*sin(t);}
real z(real t){return b*cos(n*t);}

real R(real t){
  real st2=(n*sin(n*t))^2;
  return a*(1+st2)^(1.5)/sqrt(1+st2+n^4*cos(n*t)^2);
  // return -a*(1+st2)^(1.5)/sqrt(1+st2+n^4*cos(n*t)^2); // Signed radius curvature
}

real mt=q*2*pi;
path3 p=graph(x,y,z,0,mt,operator ..)..cycle;

real m=R(0), M=R(0.5*pi/n);

// Define a pen depending to the radius curvature of graph(x,y,z) at reltime t
pen curvaturePen(real t){
  real r=abs(R(t*mt)-m)/(M-m);
  return interp(red,blue,r);
}

// Draw the tube, colors depend of the radius curvature R.
draw(tube(p,coloredpath(scale(0.1)*unitcircle, curvaturePen)));

🔗tube-fig009

Figure tube 009 Generated with Asymptote

Show tube/fig0090.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Graph (3D) | #Shading (3D) | #Array

import tube;
import graph3;

size(10cm,0);
currentprojection=perspective(4,3,4);
real x(real t) {return (1/sqrt(1+0.5*t^2))*cos(2pi*t);}
real y(real t) {return (1/sqrt(1+0.5*t^2))*sin(2pi*t);}
real z(real t) {return t;}

path3 p=graph(x,y,z,0,2.7,operator ..);
path section=scale(0.2)*polygon(4);

// Define an array of pen wich depends of a real t. t represent the "reltime" of the path3 p.
pen[] pens(real t){
  return new pen[] {interp(blue,red,t),
      interp(orange,yellow,t),
      interp(green,orange,t),
      interp(red,purple,t)};
}

// "pen[] pens(real t)" allows to color each nodes or segments with a real parameter (the reltime)
// Note that all arrays of pens are convert to cyclical arrays.
draw(tube(p,coloredpath(section,
                        pens,
                        colortype=coloredNodes)));

🔗tube-fig012

Figure tube 012 Generated with Asymptote

Show tube/fig0120.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Shading (3D)

import tube;
import graph3;
size(12cm,0);
currentprojection=orthographic(1,0,6);

real x(real t) {return sin(t);}
real y(real t) {return 0.5*sin(2*t);}

path g=graph(x,y,0,2pi,50,operator ..);
path3 p=path3(scale(5)*g);

pen[] pens(real t){
  real tt=1-2*abs(t-0.5);
  return new pen[] {interp(red,blue,tt), interp(blue,red,tt)};
}

draw(tube(p,
          coloredpath(polygon(5),pens,colortype=coloredNodes)));
label("colortype=coloredNodes",8*X);

draw(tube(shift(10*Y)*p,
          coloredpath(polygon(5),pens,colortype=coloredSegments)));
label("colortype=coloredSegments",8*X+10Y);

🔗tube-fig021

Figure tube 021 Generated with Asymptote

Show tube/fig0210.asy on Github.
Generated with Asymptote 3.00-0.
Categories : Examples 3D | Tube.asy
Tags : #Tube | #Palette | #Shading (3D) | #Graph (3D)

import tube;
import graph3;
import palette;

size(12cm,0);
currentprojection=perspective(1,1,1);

int e=1;
real x(real t) {return cos(t)+2*cos(2t);}
real y(real t) {return sin(t)-2*sin(2t);}
real z(real t) {return 2*e*sin(3t);}

path3 p=scale3(2)*graph(x,y,z,0,2pi,50,operator ..)&cycle;

pen[] pens=Rainbow(15);
pens.push(black);
for (int i=pens.length-2; i >= 0 ; --i)
  pens.push(pens[i]);

path sec=subpath(Circle(0,1.5,2*pens.length),0,pens.length);
coloredpath colorsec=coloredpath(sec, pens,colortype=coloredNodes);
draw(tube(p,colorsec));