节点使用python命令协调零件

Question

I need to access coordinates of a particular node. I have imported an orphan mesh and when I use query option in CAE and request the nodal coordinates, I get the required corrdinates. However when I request the same thing using a python command, I get some different coordinates. I am not sure what is incorrect in my command and why is there such a difference.

This is what I get when I request a query as mentioned in the fig

Coordinates of node 69 :3.732E-03,-3.118594,1.189815

And when I use the following command, I get a different value

mdb.models['Model-4'].parts['Bio_Mech1_2'].nodes[69].coordinates (-1.37620043754578, -3.04504609107971, 1.26058506965637)

or even if I call the node from the assembly

mdb.models['Model-4'].rootAssembly.instances['Bio_Mech1_2-1'].nodes[69].coordinates (-1.37620043754578, -3.04504609107971, 1.26058506965637)

Answer 1

When you're accessing nodes in a certain collection, for example part nodes as in your example, the index of the node in that collection is not the same as its label.

Query tool returns node's label and coordinates. However, the index of that exact node in a collection of part nodes is probably 68 . Try printing out the node at that location from node collection to see if that's the case.

print mdb.models['Model-4'].rootAssembly.instances['Bio_Mech1_2-1'].nodes[68]

This should tell you both the node label and the coordinates, so you could verify if you're really accessing the correct node.