I want to find out vector subtraction of co-ordinates of 2 adjacent nodes of an element. How to proceed?

Like , the element is 8-noded and I want to find out vector subtraction co-ordinates of 2 nodes(Node 1 and Node 3)

ie. |X11-X13|, |Y11-Y13| and |Z11-Z13|. How to proceed?

Answer 1

[Wan Ji]

% if you have nodes and elements
% nodes n-by-3
% elements m-by-8
% Then
node1 = 1;
node2 = 3;
xrelative = abs(nodes(node1,1) - nodes(node2,1));
yrelative = abs(nodes(node1,2) - nodes(node2,2));
zrelative = abs(nodes(node1,3) - nodes(node2,3));

Or you can do

xyzrelative = abs(nodes(node1,:) - nodes(node2,:));
xrelative = xyzrelative(1);
yrelative = xyzrelative(2);
zrelative = xyzrelative(3);

[S Priya]

>> I am getting this output

'nodes' requires Navigation Toolbox.

Error in thirty (line 3)

xrelative = abs(nodes(node1,1) - nodes(node2,1));

How to proceed?

[Wan Ji]

So what kind of tool box you are using by showing such an error?

You are using

(1) Self-defined finite element analysis

(2) A toolbox released by mathworks, e.g. pde toolboox

(3) A toolbox released by indivisuals, e.g. FEATool Multiphysics

As my answer cannot cover the all code you have written. Please show more detail about your code