Draw line between several points 3d

Hi,

I want to draw a line between several points to form a helix. I have matrix multiplication to create several S=[x;y;z] matrices. I managed to plot the points on 3D. But I couldn't connect the points together. So far, I have the following;

D=[-3.1869;5.8209;-0.9806]

theta=0

delta=0

a=0

while a<72

a=a+1

theta=theta+pi/10

delta=delta+1

Hz=[cos(theta),-sin(theta),0;sin(theta),cos(theta),0;0,0,(delta/-0.98058067569092)+1]

S=Hz*D

scatter3(S(1),S(2),S(3))

hold on

end

I tried to write "line(S(1),S(2),S(3))" inside and outside the while loop. But it didn't do. Any help will be appreciated. Thank you.

[Daniel Armyr]

First, lets format your code as code:

D=[-3.1869;5.8209;-0.9806]
theta=0
delta=0
a=0
while a<72
  a=a+1
  theta=theta+pi/10
  delta=delta+1
  Hz=[cos(theta),-sin(theta),0;sin(theta),cos(theta),0;
      0,0,(delta/-0.98058067569092)+1]
  S=Hz*D
  scatter3(S(1),S(2),S(3))
  hold on
end

Answer 1

[Daniel Armyr]

Here is code that will draw the helix with markers for each point.

D=[-3.1869;5.8209;-0.9806]
theta=0
delta=0
a=0
lastS = nan(3,1); %Add storage to save the last computed point.
view(3);
while a<72
  a=a+1
  theta=theta+pi/10
  delta=delta+1
  Hz=[cos(theta),-sin(theta),0;sin(theta),cos(theta),0;
      0,0,(delta/-0.98058067569092)+1]
  S=Hz*D
  % Use the line command to draw individual line segments.
  line( [lastS(1) S(1)], [lastS(2) S(2)], [lastS(3) S(3)], 'Marker', 'o' );    
  % And store the latest S to use to draw next line.
  lastS = S;
end

[Jamie Prince]

Thank you so much! You are a lifesaver!