abaqus-geometry

name	abaqus-geometry
description	Create and manipulate Abaqus geometry - parts, sketches, extrusions, CAD import. Use for any geometry creation task including box, cylinder, or STEP/IGES import.
allowed-tools	["Read","Write","Edit","Glob","Grep","Bash(abaqus:*)"]

Abaqus Geometry Skill

Create parts, assemblies, and import CAD files for finite element analysis.

When to Use This Skill

Route here when user mentions:

• "create a box/beam/plate/bracket"
• "draw geometry", "make a cylinder/tube"
• "import STEP/IGES file"
• "extrude", "revolve", "create assembly"
• "position the parts", "build a component"

Route elsewhere:

• Meshing the geometry -> /abaqus-mesh
• Defining materials/sections -> /abaqus-material
• Applying loads or BCs -> /abaqus-load, /abaqus-bc
• Full analysis workflow -> /abaqus-static-analysis

Key Decisions

1. How to Create Geometry?

Shape	Approach
Box, plate, beam	Sketch rectangle + extrude
Cylinder, tube	Sketch circle + extrude
Pipe, disc, shaft	Sketch profile + revolve
Complex/existing	Import STEP/IGES
Quick prototype	Primitives

Decision guidance:

• Simple prismatic shape? -> Sketch + extrude
• Axisymmetric part? -> Sketch + revolve
• Existing CAD model? -> Import STEP file

2. Where to Place Origin?

Origin Location	When to Use
Corner (0,0,0)	Asymmetric parts, easier coordinate math
Center (0,0,0)	Symmetric parts, rotation about center

3. Part vs Instance Coordinates

Context	Use
Geometry creation, section assignment	Part coordinates
BCs, loads, sets, finding faces	Instance/assembly coordinates

Important: After creating an instance, use instance.faces.findAt() not part.faces.findAt().

What to Ask User

If unclear, ask:

• Shape type? Box, cylinder, imported CAD?
• Dimensions? Length, width, height in mm
• Origin location? Corner or center?
• Import file available? Path to STEP/IGES?
• Features needed? Holes, fillets, chamfers?

Workflow

Step 1: Create Model and Part

Create the model container, then a 3D deformable part.

Step 2: Define Geometry

Choose approach based on shape:

• Sketch + Extrude: Draw 2D profile, extrude to 3D
• Sketch + Revolve: Draw profile, revolve around axis (360 degrees for full solid)
• CAD Import: Open STEP/IGES, create part from geometry file

Step 3: Add Features (Optional)

Add secondary features if needed:

• Cut holes using cut extrude
• Round edges with fillet
• Partition cells for BC/load regions

Step 4: Create Assembly Instance

Create root assembly with Cartesian datum, then create instance from part.

Step 5: Create Sets and Surfaces

Create named sets/surfaces on instance (not part) for:

• BC regions
• Load application surfaces
• Design regions (for optimization)

Finding Entities

Two methods to locate faces/edges:

1. findAt() - Exact coordinates (point must be ON the entity)
2. getByBoundingBox() - Tolerant box search (better for automation)

Combine multiple entities with + operator.

Common Pitfalls

Problem	Cause	Solution
"Sketch is not closed"	Gap in sketch entities	Ensure lines connect to form closed loop
"Cannot find face at coordinates"	Point not exactly on face	Use bounding box or verify coordinates
"Part has no cells"	Sketch not extruded	Call BaseSolidExtrude or similar
"Instance already exists"	Duplicate name	Use unique name or delete existing

Validation Checklist

Before proceeding to mesh/analysis:

• Part created with correct dimensions
• Geometry is watertight (no gaps)
• Instance created in assembly
• Sets created on instance for BC/load regions
• Partitions added if needed for region selection

Units

All dimensions use consistent units (mm-tonne-s-N-MPa):

• Length: mm
• Coordinates: mm

Code Patterns

For API syntax and code examples, see:

• API Quick Reference
• Common Patterns
• Troubleshooting Guide