Sim4Life V10.0 Release Notes

Sim4Life V10.0 takes neural response modeling from single neurons to whole-brain networks. BraiNN, the new whole-brain simulator, links applied electric fields to network activity and simulated EEG in one Sim4Life project. The AI Assistant turns plain-language instructions into Python scripts you can inspect. Desktop and web now share one refreshed interface, available in four languages.

Sim4Life Classic V10.0, the previous desktop interface, stays available and fully supported during the transition. Existing projects and scripts work in both.

Items apply to both editions unless tagged (Desktop) or (Web). A (Web; Desktop since V9.6.2) tag means desktop users already got that fix in a V9.6 maintenance release. Each release includes everything listed below it for the same edition. Desktop hardware and OS: see System Requirements.

Known Issues (Desktop B25335, Web V10.0)

• Instability for some rare dispersive material configurations.
• Potentially decreased accuracy in rare cases for the sensor combiner of the far-field sensor.
• Improper surface refinement or isosurface settings may lead to non-converged current values and inaccurate current normalization in some quasi-static simulations.
• In FDTD post-processing, the Poynting vector S(x,y,z,t) of a time-domain field sensor is formed from E and H as if sampled at the same instant; because FDTD staggers them by half a time step, it is a first-order approximation. Frequency-domain and time-averaged power results are unaffected.

V10.0 · 27 October 2026

Desktop B25335 · Web V10.0, Platform V1.98.0 (platform notes)

Added

BraiNN: Whole-Brain Network Simulation

• New whole-brain simulator. Networks of neural mass models, at region level or on the cortical surface, are driven by stimulation fields from the low-frequency solvers. Lead fields computed in the same head model project their activity to simulated scalp EEG. In V10.0, the field-induced input is constant in time.
• The GPU-accelerated engine runs orders of magnitude faster than commonly used CPU-based whole-brain simulators. Deterministic and stochastic solvers; synaptic gains, coupling strengths, and noise level are adjustable.
• Ships with a ready-to-run brain and head model and a step-by-step tutorial. EEG electrode layouts can follow three placement standards.

ThermoReg: Whole-Body Thermoregulation

• New whole-body thermoregulation simulator based on the UTCI-Fiala model. It covers active responses (sweating, shivering, vasomotion, metabolic heat) and heat exchange with the environment, in transient and steady-state analyses.
• Couples with electromagnetic and acoustic power-deposition simulations through the Virtual Population Duke model and downloadable body-region masks.

AI Assistant and Text-to-Simulation

• The Sim4Life AI Assistant generates Python scripts from plain-language instructions for CAD modeling, simulation setup and review, and post-processing. Each step is explained, and the script can be inspected and edited.
• Available everywhere in the application, including the Scripter.
• A clear message when the AI Assistant is unavailable.
• (Desktop) Requires signing in to a Sim4Life cloud account.

User Interface

• One refreshed interface for the desktop application and the web platform.
• (Desktop) Sim4Life Classic V10.0 can be installed side by side with Sim4Life V10.0. A switch in the new interface restores a layout closer to Classic at any time.
• (Desktop) Integrated Scripter, the web platform's Python scripting environment, now on the desktop: autocompletion, syntax highlighting, Save As, drag-and-drop of script files, copyable output, and direct access to the tutorial and example-notebook folders.
• Search across tools, manuals, and tutorials.
• (Desktop) Welcome screen with quick-start workflows, recent projects and scripts, tutorials, release notes, and frequently used resources. Its content and the release notes are installed locally and available without an internet connection.
• Warnings and errors appear where they occur in the simulation tree, and each workflow step shows its state.
• Reorganized ribbon and sidebar, improved drag-and-drop feedback, and explicit lock states (for example, when voxels or results exist).
• More detailed tooltips, and documentation embedded next to the tools.
• Cleaned-up material settings. The Assign Materials tool can now also assign materials to unstructured-mesh domains through material tags, not only to top-level entities.
• Virtual Population models: the Model Download Manager is sortable, and download buttons are enabled only for licensed models. (Desktop) Local copies can be imported.
• (Desktop) The desktop shows your cloud credits, announces upcoming maintenance and releases, and reports on running cloud simulations in more detail.
• (Web) Keyboard shortcuts, with an overview in the Help menu.
• (Web) 3D mice (3Dconnexion SpaceMouse) work directly in the browser.
• (Web) The model tree shows the size of unstructured meshes.

Platform and Support Center(Web)

• When a computational service runs out of memory and is stopped, you are told so.
• Email notification when someone replies to your Support Center conversation. Conversations can be archived.
• Email notification when credits are reimbursed automatically.

Localization

• Sim4Life is available in English, Korean, Chinese, and Spanish. The AI-supported translation covers the whole interface, from menus and dialogs to scientific terminology and error messages.

Simulation

• The admittance/impedance matrix is now built directly from computed current fluxes, which speeds up post-processing.
• New universal current normalizer: more reliable, and less restrictive in the choice of boundary conditions.

• The admittance matrix is computed automatically for current- or voltage-driven multi-contact electrode setups and passed directly to coupled T-Neuro and thermal simulations, without manual extraction or scripts.
• Electrode configurations can be swept or optimized against stimulation thresholds and temperature rise with the parameter sweeper or the Python API.

• Shows which material or object limits the maximal stable time step, to help trade resolution against runtime.
• Import of label fields, such as those produced by AI-based segmentation tools, as voxels that can be simulated directly; additional entities such as implants can be inserted and voxelized.
• Optional refinement at solid interfaces.

• New tools in the Mesh Doctor: Simplify Surfaces, Smooth, Subdivide, Separate Meshes, Invert Mesh, and Fix Normals.
• Progress bar for octree meshing.
• (Web; Desktop since V9.6.2) Faster cancellation of octree meshing.

Analysis

• Viewers show quantities such as eigenvalues and trace for symmetric second-rank tensors (e.g., DTI or conductivity tensors), instead of the sum of squared tensor components.
• Maximum Intensity Projection option to treat NaN values as NaN or as zero.
• Streamline Viewer improvements.
• Extended and faster homogeneous psSAR evaluation (IEC/IEEE 62704-1).
• MATCH: the evaluator gains Auto-match, which synthesizes a matching circuit for every unconnected port at the selected frequency in one click, a Circuit Library for creating and reusing loads and multi-element matching circuits, and one-click import of circuits from Touchstone files.

Python

• NIfTI slice visualization options accessible from the Python API.
• Anisotropic inhomogeneous conductivity can be set through the Python API.

Performance

• Simulations run faster and scale better.
• Large projects open faster and large result datasets load faster. 3D rendering is quicker too, including accurate transparency.

Fixed

Modeling

• Fixed nested model operations being applied incorrectly in complex models.
• Fixed the spline length input box obstructing point snapping during spline creation.
• Fixed incorrect behavior when copying a shadow entity (input to a parametric entity, e.g., Unite).
• Fixed vertex extraction errors in the Modeler when using the Python API.
• Fixed SplitWiresByContainment in the ViP module.
• (Web; Desktop since V9.6.2) Fixed projects with very large unstructured meshes failing to reopen with a "free store overflow" error.
• Enabled Edit Faceting for body patches.
• Fixed Model Download failures for some models (e.g., IXI025, ATHENA).
• (Web) Fixed hidden models reappearing in the tree when Show visible items only is enabled.

Meshing

• (Web; Desktop since V9.6.2) Fixed incorrect octree meshing of overlapping solid regions.
• (Web; Desktop since V9.6.2) The octree mesher now validates user-provided embedded meshes.
• Fixed body-meshing failures in the faceted mesher.
• (Web; Desktop since V9.6.2) Fixed inconsistent triangle orientation when extracting surfaces from prism meshes.
• Fixed Mesh Slice producing triangles smaller than expected.
• Fixed the Mesh Viewer ignoring transforms attached to unstructured meshes.
• Fixed units in multidomain meshes not matching model units.

Simulation

• (Web; Desktop since V9.6.2) Time-domain sensors no longer report zero values when results diverge in rare cases with an insufficient CFL margin.
• Terminating a multiport simulation from the Task Manager now also stops the sub-jobs of all ports.
• (Web) Fixed ports of a cancelled multiport simulation that could no longer be run.
• (Web) Fixed Switch Material Database, which did not work in Sim4Life Web.
• Fixed the Iterative Huygens simulation dialog not being displayed.
• Fixed the passive response of the rat estimator in T-Neuro.
• Enabled perfect thermal conductor in the material settings of unstructured thermal simulations.

Analysis

• Fixed viewing of the induced E-field vector from low-frequency magneto solvers.
• Fixed the Mask Filter producing NaN average SAR and keeping masked materials in the total mass.
• Fixed algorithm settings becoming locked after stopping a running homogeneous psSAR evaluation.
• Fixed the Streamline Viewer ignoring frequency snapshot options and breaking the colorbar when copying parameters between viewers.
• (Web) Fixed missing units in 2D plots.
• (Desktop) Fixed a crash when closing Sim4Life while a viewer is active.

User Interface

• (Web) Fixed a crash when uploading large files through the Open menu.
• (Web) Fixed the multi-tree not remembering the first selected item.

Python

• Fixed To Python making plus and minus boundary-plane components indistinguishable.
• Renaming a model object through the Python API now updates the name in the simulation tree.
• Fixed Jupyter notebook cells being executed out of order.
• Fixed a missing file in the "personalized transcutaneous spinal cord stimulation" tutorial.