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Node

Represents a 3D point in space with ID. It facilitates node creation, synchronization, and deletion.

Note.

All the codes below assumes the initial import and MAPI Key definition.

from midas_civil import *
MAPI_KEY('eyJ1ciI6InN1bWl0QG1pZGFzaXQuY29tIiwicGciO252a81571d')

Node

Node(x , y , z , id=None , group = '' , merge = 1)

Parameters

  • x, y, z: Coordinates of the node.
  • id (default=None): Manually assign an ID. If None, ID will be auto-assigned.
  • group (default=''): Structure group of the node (can be str or list eg. 'SG' or ['SG1','SG2'])
  • merge (default=1): If enabled, checks for existing nodes and return their IDs. No additional/duplicate node will be created.

Node.SE

Node.SE(s_loc: list, e_loc: list, n: int = 1, id=None , group = '' , merge = 1)

Parameters

  • s_loc: Start location. [x,y,z]
  • e_loc: End location. [x,y,z]
  • n (default=1): Number of division. n+1 nodes are created.
  • id (default=None): Manually assign an ID. If None, ID will be auto-assigned.
  • group (default=''): Structure group of the node (can be str or list eg. 'SG' or ['SG1','SG2'])
  • merge (default=1): If enabled, checks for existing nodes and return their IDs. No additional/duplicate node will be created.

Node.SDL

Node.SDL(s_loc: list, dir: list, l: float, n: int = 1, id=None , group = '' , merge = 1)

Parameters

  • s_loc: Start location. [x,y,z]
  • dir: Direction vector [dx, dy, dz]
  • l: Total length of created nodes (see Element.Beam.SDL).
  • n (default=1): Number of division. n+1 nodes are created.
  • id (default=None): Manually assign an ID. If None, ID will be auto-assigned.
  • group (default=''): Structure group of the node (can be str or list eg. 'SG' or ['SG1','SG2'])
  • merge (default=1): If enabled, checks for existing nodes and return their IDs. No additional/duplicate node will be created.

Node.fromList

Node.fromList(nodesList: list, id=None , group = '' , merge = 1)

Parameters

  • nodesList: List of [x, y, z] coordinates. e.g. [[0,0,0], [1,0,0], [2,0,0]].
  • id (default=None): Manually assign an ID. If None, ID will be auto-assigned.
  • group (default=''): Structure group of the node (can be str or list eg. 'SG' or ['SG1','SG2'])
  • merge (default=1): If enabled, checks for existing nodes and return their IDs. No additional/duplicate node will be created.

Object Attributes

X, Y, Z: Coordinates of the node.
ID: Unique identifier.
LOC: (x,y,z) Coordinates of the node in tuple.
AXIS: Local direction of the node eg. [(1,0,0),(0,1,0),(0,0,1)] represent local X,Y,Z respectively. Created by bLocalAxis option of Beam element.

Retrieve Node by ID

nodeByID(id:int) : Returns NODE object with given ID.

Class Attributes

Node.nodes -> List of all nodes.

n1 = Node(0,1,2,10)    # Create Node at 0,1,2 with ID = 10
n2 = Node(0,3,4,20)    # Create Node at 0,3,4 with ID = 20

for n in Node.nodes:
    print(f' NODE ID = {n.ID} | X = {n.X} , Y = {n.Y} , Z = {n.Z}')

# Output :
# NODE ID = 10 | X = 0 , Y = 1 , Z = 2
# NODE ID = 20 | X = 0 , Y = 3 , Z = 4

Methods

Node.json

Returns a JSON representation of all Nodes defined in python.

n1 = Node(0,1,2,10)    # Create Node at 0,1,2 with ID = 10
n2 = Node(0,3,4,20)    # Create Node at 0,3,4 with ID = 20

print(Node.json())

# Output :
# {'Assign': {10: {'X': 0, 'Y': 1, 'Z': 2}, 20: {'X': 0, 'Y': 3, 'Z': 4}}}

Node.create

Sends the current node list to the Civil NX using a PUT request.
New nodes are created and existing nodes(same ID) in Civil NX will be updated.

n1 = Node(0,1,2,10)    # Create Node at 0,1,2 with ID = 10
n2 = Node(0,3,4,20)    # Create Node at 0,3,4 with ID = 20

Node.create()

Node.get

Fetches nodes from the Civil NX and return the JSON representation.
-Here, Civil model had 2 nodes 

print(Node.get())
# Output
# {'NODE': {'1': {'X': 1, 'Y': 2, 'Z': 3}, '2': {'X': 1, 'Y': 3, 'Z': 2}}}

Node.sync

Retrieves Node data from the Civil NX and rebuilds the internal node list.
-Here, Civil model had 2 nodes 

Node.sync()
for n in Node.nodes:
    print(f' NODE ID = {n.ID} | X = {n.X} , Y = {n.Y} , Z = {n.Z}')

# Output
# NODE ID = 1 | X = 1 , Y = 2 , Z = 3
# NODE ID = 2 | X = 1 , Y = 3 , Z = 2

Node.clear

Deletes all node data from Python.

Node.clear()

Node.delete

Deletes all node data from both Python and Civil NX.

Node.delete()

Examples

1. Sine Grid

import math
n=50
for j in range(n):
    for i in range(n):
        Node(i,j,2*(math.sin(i/5)+math.sin(j/5)),100*i+j+1)

Node.create()
NODE GRID

2. Sphere Nodes

import math
n=50
R=5
phi=0
for j in range(40):
    for i in range(n):
        theta = i*2*math.pi/n
        Node(R*math.sin(theta)*math.cos(phi),R*math.cos(theta),R*math.sin(theta)*math.sin(phi))

    phi+=math.pi/16

Node.create()
NODE GRID

3. Rotating Nodes

import math
n=50
R=5
phi=0
for j in range(40):
    for i in range(n):
        theta = i*2*math.pi/n
        Node(R*math.sin(theta)*math.cos(phi),R*math.cos(theta),R*math.sin(theta)*math.sin(phi),i+1)

    phi+=math.pi/16
    Node.create()
NODE GRID

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Node Local Axis

In MIDAS CIVIL NX, nodes can have a local axis orientation different from the global axis. This is used to apply boundary conditions or interpret results in a skewed (rotated) coordinate system.

NodeLocalAxis(nodeID: int, type: Literal['X','Y','Z','XYZ','Vector'], angle)

Two definition methods are supported:

  • Angle (type='X', 'Y', 'Z', or 'XYZ'): Rotations about one or more global axes in degrees. Corresponds to API iMETHOD = 1.
  • Vector (type='Vector'): Explicit definition of the local X and Y axes as unit vectors. Corresponds to API iMETHOD = 3.

Parameters

  • nodeID: ID of the node to assign the local axis to.
  • type: Method used to define the local axis.
    • 'X' - Rotation angle (degrees) about the global X-axis.
    • 'Y' - Rotation angle (degrees) about the global Y-axis.
    • 'Z' - Rotation angle (degrees) about the global Z-axis.
    • 'XYZ' - Three rotation angles [rx, ry, rz] (degrees) about global X, Y and Z.
    • 'Vector' - Two direction vectors [[v1x,v1y,v1z],[v2x,v2y,v2z]] defining the local X and Y axes explicitly.
  • angle: Value matching the chosen type.
    • 'X', 'Y', 'Z' : a single angle in degrees. e.g. 30
    • 'XYZ' : list of three angles. e.g. [0, 0, 45]
    • 'Vector' : list of two vectors. e.g. [[1,0,0],[0,0,1]]

Note

If a local axis is defined again for a node that already has one, the existing definition is updated.
When type is 'X', 'Y' or 'Z', the angles of the other two axes are preserved from the existing definition.

Object Attributes

ID: Node ID to which the local axis is assigned.
TYPE: Definition method. 'ANGLE' for 'X', 'Y', 'Z', 'XYZ' and 'VEC' for 'Vector'.
ANGLE: Rotation angles [rx, ry, rz] in degrees. Used when TYPE = 'ANGLE'.
VEC: Local X and Y axis vectors [[v1x,v1y,v1z],[v2x,v2y,v2z]]. Used when TYPE = 'VEC'.

Class Attributes

NodeLocalAxis.skew -> List of all node local axis objects.
NodeLocalAxis.ids -> List of node IDs having a local axis.

NodeLocalAxis(10, 'Z', 30)
NodeLocalAxis(20, 'Vector', [[1,0,0],[0,0,1]])

for ax in NodeLocalAxis.skew:
    print(f' NODE ID = {ax.ID} | TYPE = {ax.TYPE}')

# Output :
# NODE ID = 10 | TYPE = ANGLE
# NODE ID = 20 | TYPE = VEC

Methods

NodeLocalAxis.json

Returns a JSON representation of all node local axes defined in python.
Angle based definitions use iMETHOD = 1 and vector based definitions use iMETHOD = 3.

NodeLocalAxis(10, 'Z', 30)
NodeLocalAxis(20, 'Vector', [[1,0,0],[0,0,1]])

print(NodeLocalAxis.json())

# Output :
# {'Assign': {10: {'iMETHOD': 1, 'ANGLE_X': 0, 'ANGLE_Y': 0, 'ANGLE_Z': 30},
#             20: {'iMETHOD': 3, 'V1X': 1, 'V1Y': 0, 'V1Z': 0, 'V2X': 0, 'V2Y': 0, 'V2Z': 1}}}

NodeLocalAxis.create

Sends the current node local axis list to the Civil NX using a PUT request.
New local axes are created and existing ones (same node) in Civil NX will be updated.

NodeLocalAxis(10, 'Z', 30)
NodeLocalAxis(20, 'Vector', [[1,0,0],[0,0,1]])

NodeLocalAxis.create()

NodeLocalAxis.get

Fetches node local axis data from the Civil NX and returns the JSON representation.

print(NodeLocalAxis.get())

NodeLocalAxis.sync

Retrieves node local axis data from the Civil NX and rebuilds the internal list.
Angle based (iMETHOD = 1) axes are imported as 'XYZ' and vector based (iMETHOD = 3) axes are imported as 'Vector'.
A warning is printed for nodes whose local axis type is not supported.

NodeLocalAxis.sync()
for ax in NodeLocalAxis.skew:
    print(f' NODE ID = {ax.ID} | TYPE = {ax.TYPE}')

NodeLocalAxis.clear

Deletes all node local axis data from Python.

NodeLocalAxis.clear()

NodeLocalAxis.delete

Deletes all node local axis data from both Python and Civil NX.

NodeLocalAxis.delete()

Examples

1. Rotation about a single axis

Node(0,0,0,1)
Node(5,0,0,2)

NodeLocalAxis(2, 'Z', 30)      # Rotate local axis of node 2 by 30° about global Z

Node.create()
NodeLocalAxis.create()

2. Combining rotations

Defining a single-axis rotation again for the same node keeps the previous angles of the other axes.

NodeLocalAxis(10, 'Z', 30)
NodeLocalAxis(10, 'X', 15)     # Node 10 now has X = 15° , Y = 0° , Z = 30°

print(NodeLocalAxis.json())

# Output :
# {'Assign': {10: {'iMETHOD': 1, 'ANGLE_X': 15, 'ANGLE_Y': 0, 'ANGLE_Z': 30}}}

3. Three angles at once

NodeLocalAxis(20, 'XYZ', [0, 45, 0])    # Rotate 45° about global Y

NodeLocalAxis.create()

4. Using vectors

Define the local X and Y axes directly. The local Z axis follows from these two.

NodeLocalAxis(30, 'Vector', [[1,0,0],[0,0,1]])    # Local X = global X , Local Y = global Z

NodeLocalAxis.create()

5. Skewed support at multiple nodes

import math

for i, nID in enumerate([1, 2, 3, 4]):
    NodeLocalAxis(nID, 'Z', i*15)      # Progressive rotation of 0°, 15°, 30°, 45°

NodeLocalAxis.create()