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SHD SimSHD Sim CFD
Draft. This manual is new and still being checked against the software as it is verified. Some pages will change. If something here does not match what you see, the software is right — tell us and we will fix the page.

Import STEP geometry and split it into patches

Bring a CAD solid in through the bundled OCCT translator and divide it into one patch per body, so a force can be asked about a component rather than the whole model.

Runs on the free tier.

Steps

Section titled “Steps”

  1. Select Geometry.

  2. Set Units to the units the file was exported in. Geometry is rescaled to metres on import, so this has to be right before the import, not after.

  3. Leave Heal on import on unless you have a reason not to — it sews faces and removes tiny edges in the translator.

  4. Press Import geometry and choose the file. STL, OBJ, STEP/STP, IGES/IGS and BREP are read; a .dat file is treated as an aerofoil profile and gets its own Aerofoil extrusion section instead.

  5. A CAD format is recognised but nothing is drawn until it has been tessellated. Press Translate to triSurface. This runs OCCT and can take a while on a real assembly; Stop translating aborts it.

  6. Read Geometry info. Watertight is the row that decides everything downstream — an open surface cannot be split reliably and will not mesh well either.

  7. Under Parts, press Split into parts. Each part gets a Patch n name field, and each name becomes a patch under Boundary conditions. Rename them to whatever you want the report to call them: this is the name OpenFOAM sees, so it is what a boundary condition and a force control refer to.

  8. On any part, Measure force and moment on this part creates the corresponding entry under Result control.

Merge back into one patch reverses the split.

Check it worked

Section titled “Check it worked”
  • Geometry info reports a non-zero Triangles count and a Size that matches the real body, in metres.
  • Watertight says yes.
  • Every part name appears as a child of Boundary conditions in the setup tree.

If the import or the split fails, the message is indexed in Troubleshooting.