Normal on line

Hello,

I have some points with a line and i want to draw normal vectors on that points.Like if i plot these points , i want normal to be drawn on the specified points only.

chkx=[730 710 705 686 688 679 676];
chky=[547,540,543,535,544,544,551];
chkz=[1187,1176,1187,1172,1195,1200,1216];
plot3(chkx,chky,chkz,'--rs','LineWidth',2,...
  'MarkerFaceColor','k',...
  'MarkerEdgeColor','g',...
  'MarkerSize',2)

Thanks

[Oleg Komarov]

http://www.mathworks.com/matlabcentral/answers/7885-tutorial-how-to-format-your-question

Answer 1

[Jan]

Normal to what? Your data are points in 3D, therefore a normal needs the definition of a plane. How do you define the planes for each point?

[developer]

u can chk this figure ,i want to draw normal vectors to the specific points shown in green ,actually its not the actually but one of the scans that makes the whole plane , but to study some behaviour i want to deal each scan separately ,

http://s1204.photobucket.com/albums/bb403/attayyabkhan/?action=view&current=pic.jpg

[Jan]

The picture shows a non-smooth line. I do not see a connection between this picture and the posted code.

It is still not clear, what "normal" means in your case. Usually "normal" means orthogonal to the slope in each point. But this is defined for smooth lines only. So please take the time to define, what you want exactly.

[developer]

the given code is an example while the picture is the real plot of my values , actually first i want to smooth this non smooth line as a smooth line like below

http://s1204.photobucket.com/albums/bb403/attayyabkhan/?action=view&current=pic2-1.jpg

as each point has x,y and z values so i want to implement some algorithm that make it smooth and then when i get the above desired result i can draw the normal on the same points to observe the change in angle of the whole line . I hope this i make it clear to some extent to u .

[Jan]

@Developer: You speak about x,y and z values, but you show two 2D diagrams. Therefore the problem is getting less clear.

You still do not explain what the "normal" on a 3D line should be. Imagine two points in 3D and connect them by a line. Now any line orthogonal to the connection line is "normal" - but there is an infinite number of lines, because you can rotate the normal around the connection. Let me ask a 3rd and last time: In which direction do you want to let your "normals" point?

[developer]

i actually want to construct a set of vectors

that are orthogonal to the tangential plane of each surface

point they touch.

[Jan]

How is the plane defined?