wiki:sns:intactgh:faq []

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======Intact.Simulation for Grasshopper Frequently Asked Questions======
===== 1. General =====
++1.1 Where are the simulation files saved by default?| \\
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  * The simulation/error log is available in the working directory for each problem.  The default simulation directories are located at //:C:\Users\{username}\AppData\Roaming\Intact.Simulation For Grasshopper\// \\
  * Under each, you can find the simulation working directory labeled by the time and date of the simulation run://{YYYY-MM-DD-TIME}//
  * Within each, there is a log of the simulation run://log.txt// ++

++1.2 What happens when two components are extremely close to each other but not bonded?| \\
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  * Intact.Simulation models assemblies of parts as bonded if the gap between them is small.  "Small" depends on the element size used in the simulation and the orientation of the gap. \\
  * To ensure the accuracy of disconnected physics, reduce cell size (increase resolution) to be less than the gap size. ++

=====2. Solver Settings ===== 
[[wiki:sns:intactgh:solver_settings|Solver Settings]]


++2.1 When should I use linear elements and when should I use quadratic elements?|  \\
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  * Regardless of the scenario, either will work. Generally, quadratic elements converge to a good answer quicker and with few elements, but it depends on the simulation scenario.\\

  * For geometries that undergo bending, quadratic elements perform better.\\

  * It is important to note that with quadratic elements, many fewer elements are needed to compute an accurate solution. Having more elements increases computation time, so start with a low resolution or high cell size and increase the resolution/decrease cell size to improve accuracy. \\
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📌 See example application [[wiki:sns:intactgh:ex_6|Ex-6: Linear Elements vs Quadratic Elements]] ++

++2.2 When should I use Iterative solvers vs. Direct Solver?|  \\
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  * For linear elements, the Direct Solver is recommended at a lower resolution (100-200K for 32GB RAM), and the Iterative solver at a higher resolution. \\

  * For quadratic elements, we recommend using the Direct Solver.\\ ++

++2.3 How do I know what resolution/cell size to set?| \\
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  * To accurately capture small features with linear elements, set the cell size to 1/3 the thickness of that feature.\\
  * For quadratic elements, a cell size equal to the thickness of the small feature is sufficient.\\
  * Low resolutions (<100,000) will generally solve problems quickly. Intact can typically support a resolution of 10 million elements (more on powerful computers), so start small, and gradually increase the resolution until consistent results are obtained. \\  
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📌 For more information see this post on [[wiki:sns:intactgh:resolution_and_convergence|resolution and convergence]]. \\ ++

++2.4 Is there a maximum resolution (or minimum cell size)?| \\
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  * A decent laptop/desktop should be able to support a resolution (number of elements in the grid) in order of millions. The maximum depends on your computer's memory and whether you choose to use the direct (high performance, lots of memory) or iterative (slower performance, smaller memory footprint) solver. ++

++2.5 How do I change where my simulation saves?| \\
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  * First, place a file path object on the Grasshopper Canvas.\\
  * Right click, and click "Select a directory" and connect it to Solution Directory (SD)\\
{{ :wiki:sns:intactgh:SolutionDirectory.png?400 }} ++

===== 3. Results and Visualization =====
++3.1 How can I turn on/off display mesh visualization?| \\
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  * Intact plots results using a display mesh. The result values are sampled on the mesh vertices and then linearly interpolated within the mesh facets based on the facet nodes.\\
  * To turn on or off this display mesh, see the steps in the video below\\
  * Seeing the display mesh can be useful to ensure if there a visualization artifact due to the display mesh. \\
{{ :wiki:sns:intactgh:display_mesh_viz.mp4?700 |}}++