Geometry

Geometry#

Before generating a mesh, you need to upload and validate your CAD geometry. Gradient Dynamics supports a range of industry-standard formats and provides automatic analysis and repair tools.

Supported Formats#

Format

Extensions

Best For

STEP

.step, .stp

CAD assemblies with full topology — recommended

IGES

.iges, .igs

Legacy CAD exchange

STL

.stl

Surface meshes, 3D scans

OBJ

.obj

Polygon meshes

Recommendation

Use STEP format whenever possible. STEP files preserve face topology, edge features, and multi-body assembly information. This enables per-surface mesh controls, automatic face detection, and better geometry repair.

Uploading Geometry#

  1. Open your project workspace

  2. Navigate to the Setup tab

  3. Click Upload Geometry

  4. Select your file — it will appear in the 3D viewer once processed

For STEP/IGES files, Studio automatically detects:

  • Individual solid bodies in multi-body assemblies

  • Named faces and edges from the CAD model

  • Geometric bounding dimensions for automatic domain sizing

Geometry Analysis#

After upload, navigate to the Geometry tab to run analysis. Studio checks for:

Watertightness#

The surface must be completely closed (no gaps or holes) for volume mesh generation. Open surfaces will cause the mesher to fail or produce incorrect results.

Manifold Status#

Every edge should be shared by exactly two faces. Non-manifold edges (shared by 3+ faces) or non-manifold vertices indicate topology problems.

Degenerate Elements#

Extremely small or zero-area triangles/faces that can cause meshing failures.

Geometry Repair#

If issues are detected, Studio offers automatic repair options:

Vertex Welding#

For STL/OBJ files, vertices that are close together but not connected are merged. This fixes gaps caused by floating-point precision issues in mesh exports.

  • Adjustable welding tolerance

  • Preview the welded vs. original mesh to verify results

Hole Filling#

Small holes in the surface are automatically detected and patched with new triangles.

Non-Manifold Edge Repair#

Duplicate or overlapping faces near non-manifold edges are resolved.

CAD Healing (STEP/IGES)#

For CAD files, a deeper level of repair operates on the boundary representation (B-Rep):

  • Sewing — Stitches adjacent faces that have small gaps between them

  • Gap filling — Closes gaps between face edges

  • Tolerance adjustment — Relaxes geometric tolerances to connect near-miss edges

Tip

The AI Assistant can analyze your geometry and recommend the best repair strategy. Just ask: “Check if my geometry is ready for meshing”

Multi-Body Assemblies#

When you upload a multi-body STEP file, Studio detects each solid body automatically. This is useful for:

  • Multi-region meshing — Each body becomes a separate cell zone (e.g., fluid + solid regions for conjugate heat transfer)

  • Per-body mesh controls — Different mesh sizes for different parts

  • Interface detection — Touching bodies are automatically identified for region coupling

Special Feature Detection#

Studio can automatically detect certain geometric features:

  • Wheels — Identifies wheel-like geometry on vehicles for rotating wall boundary conditions and MRF zones

  • Rotating features — Detects axially symmetric bodies that may be fans, impellers, or propellers

  • Surface faces — Groups faces by orientation and curvature for automatic surface naming

These detections can be triggered from the Geometry tab or via the AI Assistant.

Viewer Controls#

In the 3D viewer, you can interact with your geometry using:

Action

Control

Rotate

Left-click drag

Pan

Right-click drag or Shift + left-click

Zoom

Scroll wheel

Select face

Click on a surface

Camera presets

Front / Back / Left / Right / Top / Bottom / Iso buttons

Display mode

Solid, Wireframe, Translucent, or Solid + Wireframe
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