Skip to content

ZMT zurich med tech
  1. Home
  2. Sim4Life

Sim4Life

674 Topics 2.2k Posts

Subcategories

  • Installing Sim4Life and configuring licenses

    34 120
    34 Topics
    120 Posts
    G
    Did you do one of the following: • Define the FlexNet environment variable FLEXID_LIBRARY_PATH to point to the location of the dongle shared object, libhasp_linux_x86_64.so. • Define the system environment variable LD_LIBRARY_PATH to point to the location of the dongle shared object libhasp_linux_x86_64.so. ? Could you try to send us the output of lmhostid -flexid? that command should return the dongle id. You can also access the dongle firmware - if it is correctly installed - via the loopback address. On a browser, go to http://localhost:1947/ you should see the characteristics of the dongle. Let us know if it works.

  • Working with CAD models

    58 197
    58 Topics
    197 Posts
    V
    @brown Thank you for the suggestion. I can surface project object now.

  • Working with models from the Virtual Population

    56 266
    56 Topics
    266 Posts
    M
    I ended up creating my Duke model in a separate script, where I first cloned him as static. Then I removed part of the body not relevant to me by boolean subtraction (entity by entity) and finally export the remain static model to a sab file, which I load in my main script instead of the entire Duke. It has been this confusion about entities and groups and what not disturbing the flow. Thanks for your suggestions bryn

  • FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

    244 734
    244 Topics
    734 Posts
    C
    Hi In Sim4Life the tissue properties are provided as a single values. However, the IT’IS website provides supplemental information on the tissue properties. In addition to the average value, you can find the standard deviation, minima and maxima. Low Frequency (Conductivity) » IT'IS Foundation](https://itis.swiss/virtual-population/tissue-properties/database/low-frequency-conductivity/)

  • Postprocessing results

    109 320
    109 Topics
    320 Posts
    I
    Hello, What voltage values should I input as the amplitudes under Analysis->Simulation Combiner->Channel Parameters if I want to visualize the E-field for a simulation with boundary settings set to a constant flux? Here are the pertinent details and what I've already tried. I am performing an LF-electro ohmic quasi-static simulation with the rhesus macaque (Miss Able) model. I created two electrodes with cylinders to resemble the screw electrodes that we use for epidural ACS in my lab. Under the Simulation->Boundary Conditions->Boundary Settings for the two electrodes, I set the Boundary Type to Flux, with a constant flux of 2.47 mA. Then, I checked the Treat as Port box. I understand that the voltages for the amplitudes under Analysis->Simulation Combiner->Channel Parameters applies to the analysis, so it did not change the constant flux value that I input for the simulation stage. However, I don't know what voltages I should input to reflect the true E-field value for the 2.47 mA. I tried acquiring the appropriate voltages for the simulation combiner amplitudes by outputting the EM potential for each of the electrodes. This yielded a max of 0.707 V. Then, I input that value into the simulation combiner amplitudes field, setting amplitude 1 to 0.707 V and amplitude 2 to -0.707 V. Next, I clicked on EM Sensor Combiner for the overall field, EM E, and Slice Viewer. However, when I tried following these same steps for a constant flux of 1.98 mA, it also exhibited 0.707 V. So, either I'm doing something wrong or I do not understand the parameters that I am using to visualize the E-field properly. I was also wondering if perhaps the electric field was normalized for the simulation combiner, so it is not giving me the true E-field value for a given constant flux. Could you please help me output the accurate E-field value for ACS, given a constant flux of some value (in milliamps)? Thanks, Ian [image: 1749064870293-0314f288-b1f6-42c7-83a9-3f18d86d9fec-image.png] [image: 1749064913368-7f42c3ec-1900-4fe8-a967-8b1491c45760-image.png]

  • Scripting interface for Sim4Life

    137 428
    137 Topics
    428 Posts
    K
    I want to output the results of the EM simulation "EM U(t)" as a csv file, but I can't save it. Please tell me the reason. Thank you in advance. # Adding a new PlotViewer inputs = [em_sensor_extractor.Outputs["EM U(t)"]] plot_viewer = analysis.viewers.PlotViewer(inputs=inputs) plot_viewer.visible = True plot_viewer.ExportToCSV("C:/Temp/test.csv") plot_viewer.UpdateAttributes() document.AllAlgorithms.Add(plot_viewer)

  • Running Sim4Life over a network

    4 7
    4 Topics
    7 Posts
    ofliO
    Hi, Please allow me to share here the response we sent you via the Sim4Life support email so that other users can benefit from your questions. The default machine provides 500GB of storage, and you are running out of space for this project. If your results require more than 500GB, consider upgrading to a higher-tier machine with greater storage capacity. Alternatively, you could reduce the size of your simulation project by splitting it into multiple smaller simulations. This would allow you to continue using the default tier. Additionally, you might optimize your sensor settings, such as by creating smaller sensors and recording data for specific volumes of interest, rather than using an Overall Field sensor.
  • L

    Everytime I'm doing a too complex simulation the file is lost

    5
    0 Votes
    5 Posts
    2k Views
    L
    I am using Sim4Life 6.2.1.4972. It happened once when I've had put a high "maximum number of samples" in the time domain (200 I think) with the acoustic head tutorial that I changed a bit, by putting 2 transducers instead of 1. Another time it was weird because it happened with a SEFT targeting a square of skin, which was rather simple but it did crash again. My simulation was probably wrong in a way, but it didn't throw and error and just stopped. But now that I am applying @gbgbha advices, it is fine :) and thanks for the tip ! I'll try for the file that I lost
  • R

    Why does TRP exceed input power(Antenna)?

    2
    0 Votes
    2 Posts
    940 Views
    SylvainS
    The TRP is computed in a different way than the input power. Both ways are mathematically correct and would both be "exact" if there were no numerical errors. In any FDTD simulation, however, there are spatial (finite grid) or temporal (finite time step) discretization error. What you are seeing in this half-wave dipole example, is that those discretization errors are larger than the precision you would require to distinguish TRP from input power (because the radiation efficiency is very high in this case, there is almost no difference between TRP and input power). To solve this "problem", either you accept that the simulation results are accurate enough for your needs (the warning is a simple consistency check) or you increase the precision of the simulation. You can do so by increasing the grid resolution, the overall convergence level and the resolution of the far-field sensor. This will be computationally expensive, though. To help you understand, you could try to add some lossy media in your (coarse) simulation (e.g. place the dipole next to a phantom or any other dielectric). The simulation will not be more precise, but the numerical errors will be less "obvious" because they will be dwarfed by the losses occurring in the dielectric. The TRP will be lower than the input power and the warning will not be triggered. I hope this helps.
  • D

    The effect of electromagnetic field on the temperature of human tissues

    1
    0 Votes
    1 Posts
    474 Views
    No one has replied
  • A

    S4L is unable to read and load my project

    18
    0 Votes
    18 Posts
    5k Views
    ali.oezenA
    THank you very much for the hints.
  • E

    How to export images from Sim4Life Analysis Results

    image export png jpeg
    5
    0 Votes
    5 Posts
    2k Views
    M
    That works! If it's for a 2D plot, you can always right click and export the data to an excel or csv file and then work with that if you'd prefer
  • A

    Optimal performance

    3
    0 Votes
    3 Posts
    865 Views
    SylvainS
    The full version has the same performance as the Light version: it can just deal with bigger problems. Note that the low-frequency solvers are not GPU-accelerated, so if you are using that the GPU is anyway not used. If you are using the FDTD solver instead, it is accelerated by the GPU but its performance might be severely affected by the frequency of your simulation (the lower the frequency, the more iteration the FDTD method has to do in order to reach convergence). If you are in a regime where the quasi-static approximations hold, I would strongly advise you to use the LF solvers.
  • J

    Editing the excitation signal

    2
    0 Votes
    2 Posts
    673 Views
    SylvainS
    I think your signal was fine, but your settings for the Field Sensor need to be changed.
  • J

    Invalid Bounding Box Error

    2
    0 Votes
    2 Posts
    645 Views
    SylvainS
    2kHz will probably not be feasible in most propagating media, because the wavelength will simply be too large compared to the grid resolution your geometry requires (leading to unreasonably large time steps). You might want to check for e.g. what your grid look like, especially the padding at the boundaries of your computational domain.
  • H

    This topic is deleted!

    1
    0 Votes
    1 Posts
    2 Views
    No one has replied
  • S

    CEM43 / Arrhenius Thermal Damage

    1
    0 Votes
    1 Posts
    383 Views
    No one has replied
  • S

    how to model a bent wire with a fixed length?

    10
    1 Votes
    10 Posts
    2k Views
    S
    Thanks for the code. Actually I need to model some wires with the fixed length, with one part in the brain in different spots and the remaining out of the brain, It takes a long time to model each one and I'm looking for a way to make them in a shorter time. Thanks.
  • S

    grid resolution of wire and insulation

    3
    0 Votes
    3 Posts
    1k Views
    S
    Thanks for your reply.