how to solve polygon subtract problem?

I subtracted green circle from blue circle. and it returned second polygog like a moon.

but what i want to plot is thrid polygon.

how to subtract polygon liks this?

Thanks

Answer 1

[Matt J]

but what i want to plot is thrid polygon.

Plot the original polygon overlaid on top of the crescent (moon), but make the original polygon transparent.

p1=nsidedpoly(1000);
p2=nsidedpoly(1000,'Center',[1,0]);
p3=subtract(p1,p2);
plot(p3); hold on
plot(p1,'FaceAlpha',0)

Answer 2

[Matt J]

Express the 2 regions as a polyshape vector:

p1=nsidedpoly(1000);
p2=nsidedpoly(1000,'Center',[1,0]);
p3=subtract(p1,p2);
p4=intersect(p1,p2);

pFinal=[p3,p4];

h=plot(pFinal);
h(2).FaceColor='none';