-
|
I am trying to setup a simulation, yesterday somehow I got it working, now it fails and I don't understand why. All the files are here: fails.zip. This is how it looks like in AppCSXCAD (everything looks OK to the best of my understanding):
When I look at the electric field with Paraview I only see this, no propagation along the line of PEC:
This is the output of openEMS: I am getting the warning # run_simulation.py
import math
import numpy
import os, tempfile, shutil
from pathlib import Path
from pylab import *
import csv
import CSXCAD
from openEMS import openEMS
from openEMS.physical_constants import *
import threading
import time
CSX = CSXCAD.ContinuousStructure()
FDTD = openEMS()
FDTD.SetCSX(CSX)
FDTD.SetBoundaryCond("PML_8","PML_8","PML_8","PML_8","PML_8","PML_8")
FDTD.SetStepExcite(1)
# MATERIALS AND GEOMETRY
air = CSX.AddMaterial('air')
air.SetMaterialProperty(epsilon=1, mue=1)
air.AddPolyhedronReader(Path(__file__).parent/'air.stl', priority=1).ReadFile()
FR4 = CSX.AddMaterial('FR4')
FR4.SetMaterialProperty(epsilon=4.5, mue=1)
FR4.AddPolyhedronReader(Path(__file__).parent/'substrate.stl', priority=2).ReadFile()
copper = CSX.AddMetal('PEC')
copper.AddPolyhedronReader(Path(__file__).parent/'copper.stl', priority=3).ReadFile()
# GRID LINES
CSX.grid.SetDeltaUnit(unit=1e-3) # Set unit to millimeter.
AIR_POSITION = numpy.array([-25,-17,-4]) # Position of bottom left cornrer.
AIR_SIZE = numpy.array([51,35,10]) # Cube size.
air_ends = AIR_POSITION + AIR_SIZE # Position of top right corner.
COPPER_TOP_BOTTOM_PART_Z = 1.6
COPPER_TOP_TOP_PART_Z = COPPER_TOP_BOTTOM_PART_Z + .035
COPPER_BOTTOM_TOP_PART_Z = 0
COPPER_BOTTOM_BOTTOM_PART_Z = COPPER_BOTTOM_TOP_PART_Z - .035
# Grid lines for the air:
for i,xyz in enumerate(['x','y','z']):
CSX.grid.AddLine(
xyz,
list(numpy.linspace(AIR_POSITION[i], air_ends[i], 33)),
)
# Grid lines for the track and the gaps with ground plane:
CSX.grid.AddLine(
'y',
list(numpy.linspace(-3,3,22)),
)
# Fine grid for copper top:
CSX.grid.AddLine(
'z',
list(numpy.linspace(COPPER_TOP_BOTTOM_PART_Z,COPPER_TOP_TOP_PART_Z,11)),
)
# Fine grid for copper bottom:
CSX.grid.AddLine(
'z',
list(numpy.linspace(COPPER_BOTTOM_BOTTOM_PART_Z,COPPER_BOTTOM_TOP_PART_Z,11)),
)
# Fine grid for substrate:
CSX.grid.AddLine(
'z',
list(numpy.linspace(0,1.6,11)),
)
# PORTS
port_in_start = numpy.array([-20,-.5,-.034])
port_out_start = numpy.array([20,-.5,-.034])
port_size = numpy.array([1,1,1.66])
# Port in:
FDTD.AddLumpedPort(
port_nr = 1,
R = 50, # Ohm
start = port_in_start, # mm
stop = port_in_start + port_size, # mm
p_dir = 'z',
excite = 5555, # V m⁻¹
)
# Port out:
# ~ FDTD.AddLumpedPort(
# ~ port_nr = 1,
# ~ R = 50, # Ohm
# ~ start = port_out_start, # mm
# ~ stop = port_out_start + port_size, # mm
# ~ p_dir = 'z',
# ~ excite = 0, # V m⁻¹
# ~ )
# Grid lines for the ports:
for i,xyz in enumerate(['x','y','z']):
CSX.grid.AddLine(
xyz,
list(numpy.linspace(port_in_start[i], (port_in_start+port_size)[i], 5)),
)
# ~ if xyz=='x': # Only the 'x' position is different for the port out.
# ~ CSX.grid.AddLine(
# ~ xyz,
# ~ list(numpy.linspace(port_out_start[i], (port_out_start+port_size)[i], 5)),
# ~ )
# PROBES
E_field_dump = CSX.AddDump(
name = 'E_field_probe',
dump_type = 'E_field_time_domain',
)
E_field_dump.AddBox(
list(AIR_POSITION)[0:2] + [0.8], # start
list(air_ends)[0:2] + [0.8], # stop
)
PATH_TO_SIMULATION_OUTPUT_FOLDER = Path(__file__).parent/'simulation_output'
CSX.Write2XML(PATH_TO_SIMULATION_OUTPUT_FOLDER/'CSX_model.xml')
OUTPUT_DATA_DIR = PATH_TO_SIMULATION_OUTPUT_FOLDER/'data'
simulation_ongoing = True
def delete_excess_of_files():
time.sleep(1)
while simulation_ongoing:
for p in sorted(OUTPUT_DATA_DIR.iterdir()):
if '.vtr' not in p.name:
continue
if int(p.name.split('_')[-1].replace('.vtr','')) % 1000 == 0:
continue
p.unlink()
remove_excess_of_files_thread = threading.Thread(target=delete_excess_of_files)
remove_excess_of_files_thread.start()
FDTD.Run(
sim_path = OUTPUT_DATA_DIR,
cleanup = True,
)
simulation_ongoing = False |
Beta Was this translation helpful? Give feedback.
Replies: 2 comments 17 replies
-
|
We can't reproduce your model because the STL files are missing. Some general FAQ on the "unused property or primitive" topic is is here: Have you fixed the "hollow STL object" issue discussed before? One other comment, unrealted to your question: did you also include the vias that connect top ground to bottom ground? |
Beta Was this translation helpful? Give feedback.
-
|
The STL files are in the About the hollow thing, not sure how to check that. The air and the PCB substrate seem to be working (no warning for them), and were produced in the same way (exporting from FreeCAD). @Developers: My experience as a user would be better if |
Beta Was this translation helpful? Give feedback.
-
|
Sorry, I had missed the ZIP. I checked your STL and also think that your conductors are hollow, not sure if that causes any damage to the simulation. ~~ Your *.py model doesn't run here because you had used some Linux-specific stuff, but I have some general advice, based on your XML file:
I wonder if your timestep is so small (due to ultra fine z mesh in copper) that the simulation ends before the pulse can propagate along the line. I couldn't find an input for timesteps NrTS or MaxTime value defined in your simulation, so some default will apply then. From your log: FDTD timestep is: 8.69628e-16 s |
Beta Was this translation helpful? Give feedback.
-
|
Thanks for your comments, very much appreciated. How do you check whether the STLs are hollow? Is it something you see using AppCSXCAD? Other software? A screenshot would be appreciated. I changed the grid, now I have a simple uniform grid: for i,xyz in enumerate(['x','y','z']):
CSX.grid.AddLine(
xyz,
list(numpy.linspace(AIR_POSITION[i], air_ends[i], 222)),
)which seems to intersect the PEC and all the smaller details in the right way: I still get the
The FR4 seems to be there, from the reflections. So it is something only affecting the PEC. The screenshot is frame number 1400 with
Actually it is not because I use Linux specific stuff, but because I am using my fork for openEMS and for CSXCAD, which change a bit the user interface in the Python modules with the goal of, hopefully, making the life of the non-experienced user a bit easier 😅 . The following version should run on the standard openEMS: import numpy
from pathlib import Path
import CSXCAD
from openEMS import openEMS
CSX = CSXCAD.ContinuousStructure()
FDTD = openEMS()
FDTD.SetCSX(CSX)
FDTD.SetBoundaryCond(["PML_8","PML_8","PML_8","PML_8","PML_8","PML_8"])
FDTD.SetStepExcite(1)
# MATERIALS AND GEOMETRY
air = CSX.AddMaterial('air')
air.SetMaterialProperty(epsilon=1, mue=1)
air.AddPolyhedronReader(str(Path(__file__).parent/'air.stl'), priority=1).ReadFile()
FR4 = CSX.AddMaterial('FR4')
FR4.SetMaterialProperty(epsilon=4.5, mue=1)
FR4.AddPolyhedronReader(str(Path(__file__).parent/'substrate.stl'), priority=2).ReadFile()
copper = CSX.AddMetal('PEC')
copper.AddPolyhedronReader(str(Path(__file__).parent/'copper.stl'), priority=3).ReadFile()
# GRID LINES
CSX.grid.SetDeltaUnit(unit=1e-3) # Set unit to millimeter.
AIR_POSITION = numpy.array([-25,-17,-4]) # Position of bottom left cornrer.
AIR_SIZE = numpy.array([51,35,10]) # Cube size.
air_ends = AIR_POSITION + AIR_SIZE # Position of top right corner.
COPPER_TOP_BOTTOM_PART_Z = 1.6
COPPER_TOP_TOP_PART_Z = COPPER_TOP_BOTTOM_PART_Z + .035
COPPER_BOTTOM_TOP_PART_Z = 0
COPPER_BOTTOM_BOTTOM_PART_Z = COPPER_BOTTOM_TOP_PART_Z - .035
# Grid lines for the air:
for i,xyz in enumerate(['x','y','z']):
CSX.grid.AddLine(
xyz,
list(numpy.linspace(AIR_POSITION[i], air_ends[i], 222)),
)
# PORTS
port_in_start = numpy.array([-20,-.5,-.034])
port_out_start = numpy.array([20,-.5,-.034])
port_size = numpy.array([1,1,1.66])
# Port in:
FDTD.AddLumpedPort(
port_nr = 1,
R = 50, # Ohm
start = port_in_start, # mm
stop = port_in_start + port_size, # mm
p_dir = 'z',
excite = 5555, # V m⁻¹
)
# PROBES
E_field_dump = CSX.AddDump(
name = 'E_field_probe',
dump_type = 0,
)
E_field_dump.AddBox(
list(AIR_POSITION)[0:2] + [0.8], # start
list(air_ends)[0:2] + [0.8], # stop
)
PATH_TO_SIMULATION_OUTPUT_FOLDER = Path(__file__).parent/'simulation_output'
CSX.Write2XML(str(PATH_TO_SIMULATION_OUTPUT_FOLDER/'CSX_model.xml'))
FDTD.Run(
sim_path = str(PATH_TO_SIMULATION_OUTPUT_FOLDER/'data'),
cleanup = True,
) |
Beta Was this translation helpful? Give feedback.
-
|
Hi, I checked your simulation and again it's due your STL files are hollow, have to reopen them in FreeCAD, import and make solid from them. It seems that application from which you are exporting them makes them hollow, actually long time ago with @0xCoto we figured that reason why STL files seems to be for openEMS hollow is that programs which are exporting them are not settings normal for each STL triangle face and therefore there are wrong normals defined and STL file is damaged. PrusaSlicer: https://www.prusa3d.com/page/prusaslicer_424/ I tried save it and it was probably ok but model was shifted outside of zour absolute defined coordinates :( Anyway your problem is that your original application is exporting damaged STL (it's not it's fault since to export STL model and have everythig OK on all possible models is quite hard) therefore you should use always FreeCAD or some other tool to repair your STL files before using them in simulation. Corrected simulation: pcb_transfer_signal_simulation.zip I went through your script and made some corrections, here is running version, also attaching my simulation. import numpy
from pathlib import Path
import CSXCAD
from openEMS import openEMS
import threading
import time
#LuboJ added to get current directory
import os
dir_path = os.path.dirname(os.path.realpath(__file__))
CSX = CSXCAD.ContinuousStructure()
max_timesteps = 100e3
min_decrement = 1e-03 # 10*log10(min_decrement) dB (i.e. 1E-5 means -50 dB)
FDTD = openEMS(NrTS=max_timesteps, EndCriteria=min_decrement)
FDTD.SetCSX(CSX)
FDTD.SetBoundaryCond(["PML_8","PML_8","PML_8","PML_8","PML_8","PML_8"]) #LuboJ modified, changed to array
FDTD.SetStepExcite(1)
# MATERIALS AND GEOMETRY
air = CSX.AddMaterial('air')
air.SetMaterialProperty(epsilon=1, mue=1)
air.AddPolyhedronReader(os.path.join(dir_path, 'air.stl'), priority=1).ReadFile() #LuboJ modified path
FR4 = CSX.AddMaterial('FR4')
FR4.SetMaterialProperty(epsilon=4.5, mue=1)
FR4.AddPolyhedronReader(os.path.join(dir_path, 'substrate.stl'), priority=2).ReadFile() #LuboJ modified path
copper = CSX.AddMetal('PEC')
#original
#copper.AddPolyhedronReader(os.path.join(dir_path, 'copper.stl'), priority=3).ReadFile() #LuboJ modified path
#LuboJ corrected with FreeCAD
copper.AddPolyhedronReader(os.path.join(dir_path, 'topLayer.stl'), priority=3).ReadFile() #LuboJ modified path, make solids from object in FreeCAD, split to top and bottom to be able make solid
copper.AddPolyhedronReader(os.path.join(dir_path, 'bottomLayer.stl'), priority=3).ReadFile() #LuboJ modified path, make solids from object in FreeCAD, split to top and bottom to be able make solid
# GRID LINES
openEMS_grid = CSX.GetGrid() #LuboJ added
openEMS_grid.SetDeltaUnit(1e-3) # Set unit to millimeter. #LuboJ modified
AIR_POSITION = numpy.array([-25,-17,-4]) # Position of bottom left cornrer.
AIR_SIZE = numpy.array([51,35,10]) # Cube size.
air_ends = AIR_POSITION + AIR_SIZE # Position of top right corner.
COPPER_TOP_BOTTOM_PART_Z = 1.6
COPPER_TOP_TOP_PART_Z = COPPER_TOP_BOTTOM_PART_Z + .035
COPPER_BOTTOM_TOP_PART_Z = 0
COPPER_BOTTOM_BOTTOM_PART_Z = COPPER_BOTTOM_TOP_PART_Z - .035
def mesh():
x,y,z
mesh.x = numpy.array([]) # mesh variable initialization (Note: x y z implies type Cartesian).
mesh.y = numpy.array([])
mesh.z = numpy.array([])
# Grid lines for the air:
'''
for i,xyz in enumerate(['x','y','z']):
openEMS_grid.AddLine(
xyz,
list(numpy.linspace(AIR_POSITION[i], air_ends[i], 33)),
)
'''
mesh.x = numpy.linspace(AIR_POSITION[0], air_ends[0], 33)
mesh.y = numpy.linspace(AIR_POSITION[1], air_ends[1], 33)
mesh.z = numpy.linspace(AIR_POSITION[2], air_ends[2], 33)
#LuboJ remove all gridlines from AIR which are between top copper to bottom copper to not randomly generate two lines too close each other
mesh.z = numpy.delete(mesh.z, numpy.argwhere((mesh.z >= COPPER_BOTTOM_BOTTOM_PART_Z) & (mesh.z <= COPPER_TOP_TOP_PART_Z)))
# Grid lines for the track and the gaps with ground plane:
'''
openEMS_grid.AddLine(
'y',
list(numpy.linspace(-3,3,22)),
)
'''
mesh.y = numpy.delete(mesh.y, numpy.argwhere((mesh.y >= -3.2) & (mesh.y <= 3.2))) #LuboJ, first remove lines from area where is fine meshing
mesh.y = numpy.concatenate((mesh.y, numpy.linspace(-3,3,11)))
# Fine grid for copper top:
'''
openEMS_grid.AddLine(
'z',
list(numpy.linspace(COPPER_TOP_BOTTOM_PART_Z,COPPER_TOP_TOP_PART_Z,1)), #LuboJ line count changed 11 -> 1
)
'''
#mesh.z = numpy.concatenate((mesh.z, numpy.linspace(COPPER_TOP_BOTTOM_PART_Z, COPPER_TOP_TOP_PART_Z, 1)))
mesh.z = numpy.concatenate((mesh.z, [(COPPER_TOP_BOTTOM_PART_Z+COPPER_TOP_TOP_PART_Z)/2]))
# Fine grid for copper bottom:
'''
openEMS_grid.AddLine(
'z',
list(numpy.linspace(COPPER_BOTTOM_BOTTOM_PART_Z,COPPER_BOTTOM_TOP_PART_Z,1)), #LuboJ line count changed 11 -> 1
)
'''
#mesh.z = numpy.concatenate((mesh.z, numpy.linspace(COPPER_BOTTOM_BOTTOM_PART_Z, COPPER_BOTTOM_TOP_PART_Z, 1)))
mesh.z = numpy.concatenate((mesh.z, [(COPPER_BOTTOM_BOTTOM_PART_Z+COPPER_BOTTOM_TOP_PART_Z)/2]))
# Fine grid for substrate:
'''
openEMS_grid.AddLine(
'z',
list(numpy.linspace(0,1.6,11)),
)
'''
substrateZLittleShift = 0.35
mesh.z = numpy.concatenate((mesh.z, numpy.linspace(0+substrateZLittleShift, 1.6-substrateZLittleShift, 3)))
openEMS_grid.AddLine('x', mesh.x)
openEMS_grid.AddLine('y', mesh.y)
openEMS_grid.AddLine('z', mesh.z)
# PORTS
port_in_start = numpy.array([-20,-.5,-.034])
port_out_start = numpy.array([20,-.5,-.034])
port_size = numpy.array([1,1,1.66])
# Port in:
FDTD.AddLumpedPort(
port_nr = 1,
R = 50, # Ohm
start = port_in_start, # mm
stop = port_in_start + port_size, # mm
p_dir = 'z',
excite = 5555, # V m⁻¹
)
# Port out:
# ~ FDTD.AddLumpedPort(
# ~ port_nr = 1,
# ~ R = 50, # Ohm
# ~ start = port_out_start, # mm
# ~ stop = port_out_start + port_size, # mm
# ~ p_dir = 'z',
# ~ excite = 0, # V m⁻¹
# ~ )
FDTD.AddLumpedPort(
port_nr = 1,
R = 50, # Ohm
start = port_out_start, # mm
stop = port_out_start + port_size, # mm
p_dir = 'z',
excite = 0, # V m⁻¹
)
# Grid lines for the ports:
'''
for i,xyz in enumerate(['x','y','z']):
openEMS_grid.AddLine(
xyz,
list(numpy.linspace(port_in_start[i], (port_in_start+port_size)[i], 5)),
)
# ~ if xyz=='x': # Only the 'x' position is different for the port out.
# ~ CSX.grid.AddLine(
# ~ xyz,
# ~ list(numpy.linspace(port_out_start[i], (port_out_start+port_size)[i], 5)),
# ~ )
'''
openEMS_grid.AddLine('y', port_in_start[1]+port_size[1]/2)
openEMS_grid.AddLine('x', port_in_start[0]+port_size[0]/2)
openEMS_grid.AddLine('x', port_out_start[0]+port_size[0]/2) #LuboJ port out is not added now
# PROBES
E_field_dump = CSX.AddDump(
name = 'E_field_probe',
dump_type = 0, #LuboJ change to 0 = E-field probe
)
E_field_dump.AddBox(
list(AIR_POSITION)[0:2] + [0.8], # start
list(air_ends)[0:2] + [0.8], # stop
)
PATH_TO_SIMULATION_OUTPUT_FOLDER = os.path.join(dir_path, 'simulation_output') #LuboJ modified
if not os.path.exists(PATH_TO_SIMULATION_OUTPUT_FOLDER):
os.makedirs(PATH_TO_SIMULATION_OUTPUT_FOLDER)
CSX_file = os.path.join(PATH_TO_SIMULATION_OUTPUT_FOLDER, 'CSX_model.xml')
CSX.Write2XML(CSX_file)
[pcb_transfer_signal_simulation.zip](https://github.com/user-attachments/files/17611990/pcb_transfer_signal_simulation.zip)
OUTPUT_DATA_DIR = os.path.join(PATH_TO_SIMULATION_OUTPUT_FOLDER, 'data')
if not os.path.exists(OUTPUT_DATA_DIR):
os.makedirs(OUTPUT_DATA_DIR)
simulation_ongoing = True
'''
def delete_excess_of_files():
time.sleep(1)
while simulation_ongoing:
for p in sorted(OUTPUT_DATA_DIR.iterdir()):
if '.vtr' not in p.name:
continue
if int(p.name.split('_')[-1].replace('.vtr','')) % 1000 == 0:
continue
p.unlink()
remove_excess_of_files_thread = threading.Thread(target=delete_excess_of_files)
remove_excess_of_files_thread.start()
'''
from CSXCAD import AppCSXCAD_BIN
os.system(AppCSXCAD_BIN + ' "{}"'.format(CSX_file))
FDTD.Run(
sim_path = OUTPUT_DATA_DIR,
cleanup = True,
setup_only = True #LuboJ, if True it will not run simulation
)
simulation_ongoing = False |
Beta Was this translation helpful? Give feedback.
-
|
I just briefly look and yes for FreeCAD to import KiCAD there is StepUp script which I found before and it is importing whole board, but there was problem that in FreeCAD these copper layers were hollow so I used fcad_pcb library in the end, now I understand what is problem but to verify proper PCB import process need some time, with these ideas it could be resolved using gerber to proper manifold objects using one click button but need some time. |
Beta Was this translation helpful? Give feedback.
-
|
@LubomirJagos42 It's a matter of preference if you would import Gerber to STL, or better go straight to openEMS native polygons. Personally, I don't like using STL for simple polygon stuff (extruded 2D polygons). |
Beta Was this translation helpful? Give feedback.
-
@thliebig Fair. Then, it would be handy to have a string property for p in (Path(__file__).parent/'STL PEC parts').iterdir():
copper.AddPolyhedronReader(str(p), priority=3, primitive_name=p.stem).ReadFile()an openEMS would then say Could not find such a thing scrapping in the source code. |
Beta Was this translation helpful? Give feedback.
-
|
@LubomirJagos42 I found a (hopefully) reliable solution for the hollow STL issue after asking here in the FreeCAD forum. Summary:
For me in step 2 I have to select the option "Mefisto" and then up to now any "maximum edge length" is working. The default option "standard" produces a mesh that does not pass step 3, and when exported it fails with openEMS. Step 3 can be used as a replacement of the Prusa Slicer to check if the STL file is fine. Good thing about this workflow is that we can use "official tools", meaning the native STEP export in KiCad and then these tools within FreeCAD. EditAfter adding vias in KiCad, this method began to fail because of some issue in FreeCAD converting STL to mesh, see here for more details. I found a working solution:
|
Beta Was this translation helpful? Give feedback.
-
|
you could try to export top layer and bottom separately, then maybe your STL files would be valid even from original application |
Beta Was this translation helpful? Give feedback.
@LubomirJagos42 I found a (hopefully) reliable solution for the hollow STL issue after asking here in the FreeCAD forum. Summary:
For me in step 2 I have to select the option "Mefisto" and then up to now any "maximum edge length" is working. The default option "standard" produces a mesh that does not pass step 3, and when exported it fails with openEMS.
Step 3 can be …