本代码实现了，由两点和半径绘制空间任意圆柱

function [Cylinder EndPlate1 EndPlate2] = cylinder3(X1,X2,r,n,cyl_color,closed,lines)

%

% This function constructs a cylinder connecting two center points

%

% Usage :

% [Cylinder EndPlate1 EndPlate2] = cylinder3(X1+20,X2,r,n,'r',closed,lines)

%

% Cylinder-------Handle of the cylinder

% EndPlate1------Handle of the Starting End plate

% EndPlate2------Handle of the Ending End plate

% X1 and X2 are the 3x1 vectors of the two points

% r is the radius of the cylinder

% n is the no. of elements on the cylinder circumference (more--> refined)

% cyl_color is the color definition like 'r','b',[0.52 0.52 0.52]

% closed=1 for closed cylinder or 0 for hollow open cylinder

% lines=1 for displaying the line segments on the cylinder 0 for only

% surface

%

% Typical Inputs

% X1=[10 10 10];

% X2=[35 20 40];

% r=1;

% n=20;

% cyl_color='b';

% closed=1;

%

%see more information please go to www.matlabsky.cn

% NOTE: There is a MATLAB function "cylinder" to revolve a curve about an

% axis. This "Cylinder" provides more customization like direction and etc

% Calculating the length of the cylinder

length_cyl=norm(X2-X1);

% Creating a circle in the YZ plane

t=linspace(0,2*pi,n)';

x2=r*cos(t);

x3=r*sin(t);

% Creating the points in the X-Direction

x1=[0 length_cyl];

% Creating (Extruding) the cylinder points in the X-Directions

xx1=repmat(x1,length(x2),1);

xx2=repmat(x2,1,2);

xx3=repmat(x3,1,2);

% Drawing two filled cirlces to close the cylinder

if closed==1

hold on

EndPlate1=fill3(xx1(:,1),xx2(:,1),xx3(:,1),'r');

EndPlate2=fill3(xx1(:,2),xx2(:,2),xx3(:,2),'r');

end

% Plotting the cylinder along the X-Direction with required length starting

% from Origin

Cylinder=mesh(xx1,xx2,xx3);

% Defining Unit vector along the X-direction

unit_Vx=[1 0 0];

% Calulating the angle between the x direction and the required direction

% of cylinder through dot product

angle_X1X2=acos( dot( unit_Vx,(X2-X1) )/( norm(unit_Vx)*norm(X2-X1)) )*180/pi;

% Finding the axis of rotation (single rotation) to roate the cylinder in

% X-direction to the required arbitrary direction through cross product

axis_rot=cross([1 0 0],(X2-X1) );

% Rotating the plotted cylinder and the end plate circles to the required

% angles

if angle_X1X2~=0 % Rotation is not needed if required direction is along X

rotate(Cylinder,axis_rot,angle_X1X2,[0 0 0])

if closed==1

rotate(EndPlate1,axis_rot,angle_X1X2,[0 0 0])

rotate(EndPlate2,axis_rot,angle_X1X2,[0 0 0])

end

end

% Till now cylinder has only been aligned with the required direction, but

% position starts from the origin. so it will now be shifted to the right

% position

if closed==1

set(EndPlate1,'XData',get(EndPlate1,'XData')+X1(1))

set(EndPlate1,'YData',get(EndPlate1,'YData')+X1(2))

set(EndPlate1,'ZData',get(EndPlate1,'ZData')+X1(3))

set(EndPlate2,'XData',get(EndPlate2,'XData')+X1(1))

set(EndPlate2,'YData',get(EndPlate2,'YData')+X1(2))

set(EndPlate2,'ZData',get(EndPlate2,'ZData')+X1(3))

end

set(Cylinder,'XData',get(Cylinder,'XData')+X1(1))

set(Cylinder,'YData',get(Cylinder,'YData')+X1(2))

set(Cylinder,'ZData',get(Cylinder,'ZData')+X1(3))

% Setting the color to the cylinder and the end plates

set(Cylinder,'FaceColor',cyl_color)

if closed==1

set([EndPlate1 EndPlate2],'FaceColor',cyl_color)

else

EndPlate1=[];

EndPlate2=[];

end

% If lines are not needed making it disapear

if lines==0

set(Cylinder,'EdgeAlpha',0)

end