how to create shape on xy surface?

I need to calculate the area of shapes (parallelograms) that lay on one another. Their width is equal to 2. One of the angles (H) and the 'length' are variables (attached). So at the first I have created the list of the tasks:

1. create the shape for the each case
2. lay the shapes one on another
3. and calculate the created shape's area

I have no idea how to do it, but looking into different options.

You are welcome to help with any of 3 tasks or with all of them.

I came accross with this

https://www.mathworks.com/matlabcentral/answers/1886402-creating-a-projection-of-a-surface-on-a-plane-for-area-calculation?s_tid=sug_su

but I am still far away from understanding how to handle my task.

If it is simple for you, code it please, otherwise any hints and links to similar questions will be very helpful.

Thanks in advance.

[Les Beckham]

Can you explain (preferably with a sketch) what you mean by "angles" and "length"?

Also, more than half of your length values are zero (see below).

S = load('variable.mat');
plot(S.H, '.')
hold on
grid on
plot(S.length(S.length ~= 0), '.')

[Asliddin Komilov]

Hi, thanks for the reply

sorry for the inconvinience, this will sort the data:

angle=angle(length>0);
length=length(length>0);

so, the coordinates of the baseline (width at the bottom) stays the same.

thanks in advance

Answer 1

[Chunru]

websave("variable.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1538662/variable.mat");
S = load('variable.mat');
% idx = S.H ~= 0 & S.length ~=0;
idx = S.length ~=0;      

% Do computations only on the nonzero length and angle
S.H = 90 + S.H(idx)';       % check your definition of angle
S.length = S.length(idx)';

[S.H  S.length]

ans = 108×2

23.1578 12.4611 24.4078 6.2578 25.6578 4.1901 26.9078 3.1563 28.1578 2.5361 29.4078 2.1227 30.6578 1.8275 31.9078 1.6062 33.1578 1.4341 34.4078 1.2966

min(abs(S.H)), max(abs(S.H))

ans = single 23.1578

ans = single 156.9078

whos

  Name        Size             Bytes  Class      Attributes

  S           1x1               1200  struct               
  ans         1x1                  4  single               
  cmdout      1x33                66  char                 
  idx         1x289              289  logical              

% create the shape for the each case
n = length(S.H)

n = 108

w = 2;
S.X = [zeros(n,1) 2+zeros(n,1) S.length.*cosd(S.H)+2  S.length.*cosd(S.H)];
S.Y = [zeros(n,1) zeros(n,1) S.length.*sind(S.H)  S.length.*sind(S.H)];

% lay the shapes one on another
figure
plot(S.X(:, [1:end 1])', S.Y(:, [1:end 1])')    % plot all shapes

% plot shapes evry other 10
figure
plot(S.X(1:10:end, [1:end 1])', S.Y(1:10:end, [1:end 1])')  
axis([-2 4 0 2])

% and calculate the created shape's area
S.A = abs(S.length.*w.*sind(S.H));
figure;
plot(S.A);
xlabel("Shape Index"); ylabel("Area")

[Asliddin Komilov]

I have the same problem, the values of 'angle' are from 20 to 90 degrees, but it is the same in all plotted shapes

[Chunru]

The angle range from +/-0 - 67 deg. What do you mean "same in all plotted shapes"?

[Asliddin Komilov]

Hi,

my bad, you are right the range is from 0 to 67. In your plot, only the size of the figures change, but expected something like this:

I just realized that at zero angle the shape should be rectangle. And the problem was that angle=90+H. Sorry for this, I understood it only now.

Thanks.

PS. I still don't know how to do it.

[Chunru]

See the updated.

[Asliddin Komilov]

That is great.

Please, tell me what shape index is.

I'd rather have a one value for the total area, so shall I sum S.A?

Thank you.

[Chunru]

You have 108 shapes with length>0. The shape index (i from 1 to 108) is the reference to the i-th shape you have.

You can sum all the area by: sum(S.A)

[Asliddin Komilov]

thanks