cylinder-o-grid

Cylinder O-Grid

Create a reviewable coin-style O-grid and accept it only after topology, mesh, and analysis checks pass in the selected CAE workflow.

Establish the task

Collect or infer only low-risk inputs:

• Identify the target preprocessor, solver, analysis type, and whether the task is plan-only or a live implementation.
• Distinguish a new cylinder from an existing production part.
• Record radius R, length L, cylinder axis, units, and any interfaces or local refinement zones.
• Record the requested brick family and the exact solver-specific formulation when known.
• Record either target element size or counts for one square side/90-degree arc, radial layers, and axial layers.
• Ask before changing geometry, deleting an existing mesh, replacing a model, or relaxing a quality gate.

If live access to the target CAE application is unavailable, generate a plan and preview, label them as unexecuted in that application, and do not claim that the mesh was created or validated there.

Enforce the topology

Use a circular cross-section with one centered, axis-aligned square. Connect each square vertex to the circle along the same 45-degree radial direction. Preserve these invariants:

• Keep 0 < a < R/sqrt(2), where a is the square half-width.
• Create five sweepable cross-section regions: one center block and four outer sectors.
• Use the same count n_side on every square side and corresponding 90-degree outer arc.
• Use the same n_radial on all four vertex-to-circle connector edges.
• Use the same n_axial on all edges parallel to the cylinder axis.
• Keep partitions continuous through the full cylinder length and share nodes at every internal boundary.
• Reject free tetrahedral fallback unless the user explicitly changes the objective.

Read references/topology.md before selecting the square size or element counts.

Route to the target software

• For every target, first produce and review the software-independent plan with scripts/plan_ogrid.py.
• For Abaqus/CAE, read references/abaqus.md. Use scripts/abaqus_build_ogrid.py only for a clean, straight cylinder aligned with global Z; adapt the workflow for existing or differently oriented parts.
• For another CAE preprocessor, translate the five logical blocks, edge roles, mapped quadrilateral controls, axial sweep, and quality gates into its native operations. Use only available registered tools or documented native APIs. No non-Abaqus automated builder is bundled, so deliver plan-only evidence if live construction and readback cannot be proved.