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Sim4Life

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  • Installing Sim4Life and configuring licenses

    36 126
    36 Topics
    126 Posts
    D
    Thank you so much!
  • Working with CAD models

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    62 Topics
    220 Posts
    Y
    Hello, I am using a script to place electric dipoles within specific structures in an anatomical model, such as the gastrointestinal (GI) tract (including the stomach, small intestine, etc.). The question is, how can I get the coordinates of the space occupied by the model of the GI tract, or in other words, how can I verify that the electric dipoles I place are inside the tissue of the GI tract? Thanks for your help!
  • Working with models from the Virtual Population

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    58 Topics
    273 Posts
    brynB
    The tutorials are, unfortunately, not automatically synchronized to the cloud version yet. We can make the new ones available soon, though. Sorry for the inconvenience. If you send me an email (lloyd @ zmt.swiss), I can forward the notebook to you. Cheers, Bryn
  • FDTD, Low-Frequency, Neuron, Mode-Matching, Flow, Acoustics, etc...

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    759 Posts
    B
    If simulations are queued indefinitely, this could be an indication of a license issue. To run a simulation, the solver needs to 'check out' a license feature from the license server. When it completes, it marks that license feature as available again. Sometimes, if the application were to crash for some reason, the license feature is not correctly marked as available, preventing other simulations from proceeding because they think the feature isn't currently available to checkout. To resolve this, one thing to try would be to stop and restart license software, or to reinstall the license to ensure that all license features are reset.
  • Postprocessing results

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    117 Topics
    350 Posts
    AntoninoMCA
    Dear @lorenero_99, Thank you for contacting us! Please have a read to my recent comment to this post, where I tried to be very detail in explaining how the current flux normalization works and what are the limitations. https://forum.zmt.swiss/topic/733/normalization-for-precise-current-control-via-jupyter/5 For what concerns the impedance, if you use the Ohmic-Current Dominated solver, the Ohmic laws apply and you can extract the resistance (impedance) knowing the applied voltages at the electrodes and the current through them. If you need further explanations, please do not hesitate to contact us immediately! All the best, Antonino
  • Scripting interface for Sim4Life

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    137 Topics
    431 Posts
    SylvainS
    Hi, I strongly recommend you have a look at the tutorial 3.2.12 called Temporal Interference with Complex Head Model. It should be of significant help for setting up a TI simulation correctly. As for your specific questions: yes, that's correct. You can actually get the full Python script that generates a given simulation from the GUI by right-clicking on the simulation in the Explorer tree and selecting "To Python". Very useful :) That will most likely not work. Instead, you should apply fixed voltage Dirichlet conditions (e.g. +/- 1V) and re-normalize your results at post-processing (see screenshot below) For most fields that you can see in the analysis, you can use the Imp/Export menu in the ribbon and find a format in which to export (e.g. Matlab, VTK, or even plain text). [image: 1756718002390-0c790cba-feab-4bf1-a1c2-c6c1b959649c-image.png] [image: 1756718129268-fdbe02f0-7b3a-4d2e-a68d-989752dd05a7-image.png]
  • Running Sim4Life over a network

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    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.
  • 'Point Sensor Tool' is not available

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    M
    Sorry, don't have S4L with neuron available at the moment, but I looked at the tutorial and it seems to have changed. When you create the sensor settings can you try to drag and drop the axon to the sensor setting and then chose the section name? (That was the old way of doing it) Still, you should be able to run the simulation without a point sensor.. Sorry can't help more
  • Everytime I'm doing a too complex simulation the file is lost

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    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
  • Why does TRP exceed input power(Antenna)?

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    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.
  • The effect of electromagnetic field on the temperature of human tissues

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  • S4L is unable to read and load my project

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    ali.oezenA
    THank you very much for the hints.
  • How to export images from Sim4Life Analysis Results

    image export png jpeg
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    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
  • Optimal performance

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    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.
  • Editing the excitation signal

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    SylvainS
    I think your signal was fine, but your settings for the Field Sensor need to be changed.
  • Invalid Bounding Box Error

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    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.
  • This topic is deleted!

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  • CEM43 / Arrhenius Thermal Damage

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  • how to model a bent wire with a fixed length?

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    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.
  • grid resolution of wire and insulation

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    S
    Thanks for your reply.