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stlFileImport.py

You can view and download this file on Github: stlFileImport.py

#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
# This is an EXUDYN example
#
# Details:  demo showing import of simple STL file using specialized interface functions
#
# Author:   Johannes Gerstmayr
# Date:     2022-07-03
#
# Copyright:This file is part of Exudyn. Exudyn is free software. You can redistribute it and/or modify it under the terms of the Exudyn license. See 'LICENSE.txt' for more details.
#
#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

import exudyn as exu
from exudyn.itemInterface import *
from exudyn.utilities import * #includes itemInterface and rigidBodyUtilities
import exudyn.graphics as graphics #only import if it does not conflict #includes graphics and rigid body utilities
import numpy as np

SC = exu.SystemContainer()
mbs = SC.AddSystem()


#%%++++++++++++++++++++++++++++++++++++++++++++++++++++
#physical parameters
g =     [0,-9.81,0] #gravity
L = 1               #length
w = 0.1             #width
bodyDim=[L,w,w] #body dimensions
p0 =    [0,0,0]     #origin of pendulum
pMid0 = np.array([L*0.5,0,0]) #center of mass, body0

#ground body
oGround = mbs.AddObject(ObjectGround())

#%%++++++++++++++++++++++++++++++++++++++++++++++++++++
#first link:
iCube0 = InertiaCuboid(density=5000, sideLengths=bodyDim)
iCube0 = iCube0.Translated([-0.25*L,0,0]) #transform COM, COM not at reference point!

#graphics for body
fileName = 'solution/stlImport.stl'
if True: #True=create STL file; False=load STL file
    graphicsBody0 = graphics.Brick([0,0,0], bodyDim, graphics.color.dodgerblue)
    graphics.ExportSTL(graphicsBody0, fileName)

graphicsBody0 = graphics.FromSTLfileASCII(fileName, graphics.color.dodgerblue) #color not stored in STL file
#faster version (for large STL files):
#use binary files and install numpy-stl library: [allow options like scale, offset, ...]
# graphicsBody0 = graphics.FromSTLfile(fileName, graphics.color.dodgerblue, scale=1., Aoff=np.eye(3), pOff=[0,0,0])

#+++++++++++++++++++++++
graphicsBody0 = AddEdgesAndSmoothenNormals(graphicsBody0, edgeAngle = 0.25*pi, addEdges=True, smoothNormals=True)


graphicsCOM0 = graphics.Basis(origin=iCube0.com, length=2*w)

[n0,b0]=AddRigidBody(mainSys = mbs,
                     inertia = iCube0, #includes COM
                     nodeType = exu.NodeType.RotationEulerParameters,
                     position = pMid0,
                     rotationMatrix = np.diag([1,1,1]),
                     gravity = g,
                     graphicsDataList = [graphicsCOM0, graphicsBody0])


#%%++++++++++++++++++++++++++
#revolute joint (free z-axis)

#revolute joint option 3:
AddRevoluteJoint(mbs, body0=oGround, body1=b0, point=[0,0,0],
                  axis=[0,0,1], useGlobalFrame=True, showJoint=True,
                  axisRadius=0.2*w, axisLength=1.4*w)

#assemble system before solving
mbs.Assemble()
simulationSettings = exu.SimulationSettings() #takes currently set values or default values

tEnd = 4 #simulation time
h = 1e-3 #step size
simulationSettings.timeIntegration.numberOfSteps = int(tEnd/h)
simulationSettings.timeIntegration.endTime = tEnd
simulationSettings.timeIntegration.verboseMode = 1
#simulationSettings.timeIntegration.simulateInRealtime = True
simulationSettings.solutionSettings.solutionWritePeriod = 0.005 #store every 5 ms

SC.visualizationSettings.window.renderWindowSize=[1600,1200]
SC.visualizationSettings.openGL.multiSampling = 4
SC.visualizationSettings.openGL.lineWidth = 3
SC.visualizationSettings.general.autoFitScene = False

SC.visualizationSettings.nodes.drawNodesAsPoint=False
SC.visualizationSettings.nodes.showBasis=True

exu.StartRenderer()
if 'renderState' in exu.sys: #reload old view
    SC.SetRenderState(exu.sys['renderState'])

mbs.WaitForUserToContinue() #stop before simulating

mbs.SolveDynamic(simulationSettings = simulationSettings,
                 solverType=exu.DynamicSolverType.TrapezoidalIndex2)

SC.WaitForRenderEngineStopFlag() #stop before closing
exu.StopRenderer() #safely close rendering window!