ASY-Forum

import three;
size(8cm,0);
currentprojection=obliqueX;
currentlight=nolight;
triple v1=(10,0,0),
       v2=(0,10,0),
       pO=(-2,-3,0);
path3 pl1=plane(v1,v2,pO);
path3 ch=(5,3,4)..(5,4,8)..(1,4,4)..(4,-2,3)..cycle;
 
transform3 proj=planeproject(pl1); 
path3 chproj=proj*ch;
 
draw(surface(pl1),paleblue+opacity(.5),red);
draw(ch,1bp+blue);
draw(chproj,1bp+red);
for (int i=0; i < length(ch); ++i)
  draw(point(ch,i)--point(chproj,i), .5bp+blue+dotted);

import graph3;
 
size3(200,IgnoreAspect);
 
currentprojection=orthographic(4,6,3);
 
real x(real t) {return 1+cos(2pi*t);}
real y(real t) {return 1+sin(2pi*t);}
real z(real t) {return t;}
 
path3 p=graph(x,y,z,0,1,operator ..);
 
draw(p,Arrow3);
draw(planeproject(XY*unitsquare3)*p,red,Arrow3);
draw(planeproject(YZ*unitsquare3)*p,green,Arrow3);
draw(planeproject(ZX*unitsquare3)*p,blue,Arrow3);
 
axes3("$x$","$y$","$z$");