gk-v

Use ytick(Label(align=W),(0,4),W);

Just copied an example NURBSsurface.asy to http://asymptote.ualberta.ca and get an error message: triple[][] P=scale3(20)*octant1.P; ^ workspace_1.asy: 63.32: no matching variable 'octant1.P'

This could be done in many ways, here is one: import Lsystem; size(10cm,0); Lsystem SierpinskiCurve1= Lsystem("YF", new string[][]{{"X","YF+XF+Y"},{"Y","XF-YF-X"}}, La=60, Lai=0); Lsystem SierpinskiCurve2= Lsystem("YF", new string[][]{{"X","YF+XF+Y"},{"Y","XF-YF-X"}}, La=60, Lai=0); Lsystem SierpinskiCurve3= Lsystem("YF", new string[][]{{"X","YF+XF+Y"},{"Y","XF-YF-X"}}, La=60, Lai=0); SierpinskiCurve1.iterate(1); path g=SierpinskiCurve1.paths()[0]; SierpinskiCurve2.iterate(2); path h=SierpinskiCurve2.paths()[0];...

The png image above was produced with the standard options for such 3D surfaces asy -f png -render=4 Also, you can get a vector pdf file with just the curves of intersection: settings.outformat="pdf"; settings.prc=false; import graph3; size(200); currentprojection=orthographic((0.5,0.5,1)); real f(real x, real y, real z) {return y^2 + (z - 2)^2 - 4;} real g(real x, real y, real z) {return (x^2 + y^2 + z^2 + 8)^2 - 36*(x^2 + y^2);} arrowbar arr=Arrow(HookHead,size=2); draw(project(O--X),red+0.7bp,arr);...

Luckily, in this case we can find the intersection of the two surfaces in parametric form, expressing $x$ and $y$ coordinates of the intersection curve(s) in terms of $z$ and using $z$ as a parameter, varying from $0$ to $1$. The intersection curve is then a piece-wise parametric curve. Here is the code: import graph3; import smoothcontour3; size(200); currentprojection=orthographic((0.5,0.5,1)); real f(real x, real y, real z) {return y^2 + (z - 2)^2 - 4;} real g(real x, real y, real z) {return (x^2...

Cyclic array is a convenient feature, as well as the in-place anonymous array. Question: Is there any standard way to set a cyclic flag for a new anonymous array used, say, as an argument of a function? For example, let's assume that function f accepts an array argument a and either fill the closed area or just draw the outline, depending on the .cyclic flag of that array: import graph; void f(pair[] a, pen p=currentpen){ guide g=graph(a); if(a.cyclic){ g=g..cycle; fill(g,p); } else draw(g,p); }...

Try var mypen=rgb(.6,.6,1)+opacity(.7); // or // var mypen=emissive(white+opacity(.6)); //

You can also check out a couple of related examples at TeX.SE: filling-in the closed parts of a typeface glyph and can-i-visualize-the-bezier-control-points-of-a-letter-in-tex.