does convex hull intersect?

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CHANDRABHAN Singh
CHANDRABHAN Singh 2022-1-13
评论： CHANDRABHAN Singh 2022-1-21
Hello. The codes shown produces two convhull. I want to generate a parameter p such that
if convhull intersect, p=false
else, p=true. Any help or suggetions regarding this. Thanks in advance.
figure
for ii=1:2
rand_theta(ii,:) = sort(rand(1,10)).*2*pi;
rand_beta(ii,:) = sort(rand(1,10)).*pi - pi/2;
radius = 5;
[x(ii,:), y(ii,:), z(ii,:)] = sph2cart(rand_theta(ii,:), rand_beta(ii,:),radius);
%[X, Y, Z] = meshgrid(x,y,z);
k = convhull(x(ii,:), y(ii,:), z(ii,:));
trisurf(k, x(ii,:), y(ii,:), z(ii,:));
hold on;
end

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采纳的回答

Matt J
Matt J 2022-1-13
编辑：Matt J 2022-1-13
You can use intersectionHull() from
https://www.mathworks.com/matlabcentral/fileexchange/30892-analyze-n-dimensional-convex-polyhedra?s_tid=srchtitle
for ii=1:2
V{ii}=[x(ii,:); y(ii,:); z(ii,:)]';
end
S=intersectionHull('vert',V{1},'vert',V{2});
If S.vert is empty, there is no intersection.
  3 个评论
显示 1更早的评论
Matt J
Matt J 2022-1-20
I cannot see where, in this code, you call intersectionHull().
CHANDRABHAN Singh
CHANDRABHAN Singh 2022-1-21
@Matt J
I have specified piece of code using intersectionhull below. Line 58 of the code.
for ii= 1:numel(agg_num)
V{1}=[x_plot(agg_num(ii),1:theta_m(agg_num(ii),1)); y_plot(agg_num(ii),1:theta_m(agg_num(ii),1)); z_plot(agg_num(ii),1:theta_m(agg_num(ii),1))]';
V{2}=[x_plot(jj,1:theta_m(jj,1)); y_plot(jj,1:theta_m(jj,1)); z_plot(jj,1:theta_m(jj,1))]';
S=(intersectionHull('vert',V{1},'vert',V{2}));
s=isempty(S.vert);
while_inner_loop = s;

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更多回答（1 个）

Bjorn Gustavsson
Bjorn Gustavsson 2022-1-13
You should have two file-exchange packages that solves your problem:
fast-and-robust-curve-intersections
curve-intersections
They should be able to return the intersection-points of your conv-hull curves. I don't know how they behave for peculiar edge-cases like osculating curves and potentially similar corners (and how you want to solve those considering our finite precision...)
HTH

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