How to draw a sphere using asymptote from tutorial

Question

I'm just following the tutorial from Charles Staats III

In the page of 55, the codes:

settings.outformat = "pdf";
settings.prc = false;
settings.render = 0;
import three;
size(5cm,0);
path3 myarc = rotate(18,Z) * Arc(c=O, normal=X, v1=-Z, v2=Z, n=10);
surface backHemisphere = 
    surface(myarc, angle1=0, angle2=180, c=O, axis=Z, n=10);
surface frontHemisphere = 
    surface(myarc, angle1=180, angle2=360, c=O, axis=Z, n=10);
draw(backHemisphere, 
     surfacepen=material(white+opacity(0.8), 
     ambientpen=white), 
     meshpen=gray(0.4));
draw(O--X, blue+linewidth(1pt));
draw(frontHemisphere, 
     surfacepen=material(white+opacity(0.8), ambientpen=white), 
     meshpen=gray(0.4));

Cannot run properly, the error is:

fig01.asy: 6.17: no matching variable 'Arc'

If I edit the like from

path3 myarc = rotate(18,Z) * Arc(c=O, normal=X, v1=-Z, v2=Z, n=10);

to

path3 myarc = rotate(18,Z) * arc(c=O, normal=X, v1=-Z, v2=Z, n=10);

It will give message:

fig01.asy: 6.33: no matching function 'arc(triple c, triple normal, triple v1, triple v2, int n)'

Anyone know where is wrong?

Answer 1

Ok, after check with documents, I know why that is happen. To use the function Arc in path3, it required extra package,

import graph3;

Also, Arc, Circle function in 2D case require package graph

import graph;

They can solve this.