Jlink - Java Automation Toolkit for Creo Parametric

Jlink (Object TOOLKIT Java) is a free Java API that enables programmatic automation of Creo Parametric design tasks. It provides Session-based access to models, features, parameters, assemblies, and drawings.

Quick Start

New to Jlink? Start here:

1. Read Architecture Overview below
2. Study Basic Patterns for initialization
3. Review Common Tasks Decision Tree
4. Check Reference Guide for specific operations

Core Concepts

Session Model (Entry Point)

All Jlink operations flow through a single Session object:

// Get active session (main pattern)
Session session = pfcSession.GetCurrentSessionWithCompatibility(
    CreoCompatibility.C4Compatible
);

// Now use session for all operations
Model model = session.RetrieveModel(descriptor);

Exception Handling (Universal)

All Jlink methods throw jxthrowable:

try {
    // Any Jlink operation
    Model model = session.RetrieveModel(descriptor);
    Feature feat = model.GetFeatureByName("MY_FEATURE");
} catch (jxthrowable x) {
    x.printStackTrace();
    // Handle error
}

Object Hierarchy

Session (connection to Creo)
├── Model (Part, Assembly, or Drawing)
│   ├── FeatureTree (all features)
│   ├── ParameterTable (model parameters)
│   └── Drawing-specific (sheets, views, notes)
├── UICommand (menu/toolbar integration)
└── Selection (interactive user selection)

Architecture Overview

Packages (20+ modules, but focus on core 6)

Package	Purpose	Key Classes
pfcSession	Session management	Session, Selection, UICommand
pfcModel	Models (parts, assemblies, drawings)	Model, ModelDescriptor, ModelType
pfcFeature	Feature creation & manipulation	Feature, FeatureCreate, FeatureType
pfcParameter	Parameters & dimensions	Parameter, ParamValue, DimensionType
pfcGeometry	Geometry operations	Point, Vector, Transform
pfcAsyncConnection	Async/remote operations	AsyncConnection, AsyncServer

Session Lifecycle

// 1. Retrieve session (usually already exists)
Session session = pfcSession.GetCurrentSessionWithCompatibility(
    CreoCompatibility.C4Compatible
);

// 2. Work with models/features/parameters
try {
    // Do work
} catch (jxthrowable x) {
    // Handle errors
}

// 3. Cleanup (usually automatic in application context)
// No explicit disconnect needed for current session

Basic Patterns

1. Model Operations

Retrieve existing model:

// By name and type
ModelDescriptor descr = pfcModel.ModelDescriptor_Create(
    ModelType.MDL_PART,
    "my_part",
    null  // No directory
);
Model model = session.RetrieveModel(descr);

// Get current model in Creo
Model current = session.GetCurrentModel();

Create/save model:

ModelDescriptor descr = pfcModel.ModelDescriptor_Create(
    ModelType.MDL_PART,
    "new_part",
    null
);
Model newModel = session.CreateModel(descr, null);

// Save to working directory
newModel.Save();  // or SaveAs(descriptor)

Model types:

• ModelType.MDL_PART - Part file
• ModelType.MDL_ASSEMBLY - Assembly file
• ModelType.MDL_DRAWING - Drawing file

2. Feature Access & Creation

Get feature by name:

try {
    Feature feat = model.GetFeatureByName("EXTRUDE_1");
} catch (jxthrowable x) {
    // Feature not found
}

Iterate features:

FeatureTree featTree = model.GetFeatureTree();
Sequence<Feature> features = featTree.GetFeatures();

for (int i = 0; i < features.GetMembersCount(); i++) {
    Feature f = features.GetMember(i);
    // Process feature
}

Create feature (example: extrude):

FeatureCreateData createData = pfcFeature.FeatureCreate_Create(
    FeatureType.EXTRUDE,
    ModelRef.CURRENT,  // Current model
    "", null, null
);

// Set extrude depth
createData.SetIntParam("depth_type", 1);  // ONE_SIDED
createData.SetDoubleParam("depth_1", 10.0);  // 10 units

// Create and return feature
Feature newFeat = model.CreateFeature(createData);

3. Parameter Operations

Get parameter value:

try {
    Parameter param = model.GetParam("THICKNESS");
    ParamValue val = param.GetValue();
    double thickness = val.GetDoubleValue();
} catch (jxthrowable x) {
    // Parameter not found
}

Set parameter value:

Parameter param = model.GetParam("THICKNESS");
ParamValue newVal = pfcParameter.ParamValue_CreateDoubleParamValue(2.5);
param.SetValue(newVal);

Model parameters:

// Get all parameters
ParameterTable paramTable = model.GetParameters();
Sequence<Parameter> params = paramTable.GetParams();

for (int i = 0; i < params.GetMembersCount(); i++) {
    Parameter p = params.GetMember(i);
    // Access param
}

4. Interactive Selection

Get user selection:

UICommand cmd = session.UICreateCommand("custom.select", selectionListener);

// Selection types
SelectionOptions opts = pfcSelection.SelectionOptions_Create();
opts.AddFilterType(SelectionType.EDGE);  // Allow edge selection
opts.SetMaxSelectCount(5);  // Max 5 edges

Selection selection = session.UISelect(opts, null);

Process selections:

int count = selection.GetSelectionCount();
for (int i = 0; i < count; i++) {
    SelectedObject selObj = selection.GetSelectionItem(i);
    GeometryType geomType = selObj.GetSelectionType();
    // Use selected geometry
}

5. Assembly Operations

Add component:

ModelDescriptor compDescr = pfcModel.ModelDescriptor_Create(
    ModelType.MDL_PART,
    "component_name",
    null
);

ComponentFeat compFeat = (ComponentFeat)model.CreateFeature(
    pfcFeature.FeatureCreate_Create(
        FeatureType.COMPONENT,
        ModelRef.CURRENT,
        "", compDescr, null
    )
);

Apply constraints:

Constraint constraint = pfcConstraint.Constraint_CreateMateConstraint(
    surfaceRef1,  // First reference
    surfaceRef2   // Second reference
);
model.AddConstraint(constraint);

6. Drawing Automation

Create drawing view:

// Open template or create drawing
ModelDescriptor drawDescr = pfcModel.ModelDescriptor_Create(
    ModelType.MDL_DRAWING,
    "drawing_name",
    null
);
Model drawing = session.CreateModel(drawDescr, null);

// Add view (simplified)
DrawingSheet sheet = drawing.GetCurrentSheet();
DrawingView view = sheet.CreateGeneralView(modelRef, viewData);

Common Tasks Decision Tree

Choose task → find reference file → implement pattern

Model Management

• Open/retrieve model → session.RetrieveModel(descriptor)
• Create new model → session.CreateModel(descriptor, null)
• Save model → model.Save() or model.SaveAs(descriptor)
• Check if modified → model.GetModified() → bool

Feature Operations

• Get feature by name → solid.GetFeatureByName(name)
• Iterate all features → solid.ListFeaturesByType(true, null)
• Create feature → solid.CreateFeature(FeatureCreateInstructions)
• Delete feature → feature.CreateDeleteOp() then execute
• Get feature dimensions → feature.ListSubItems(ITEM_DIMENSION) (returns ModelItems)

Parameters

• Get parameter → model.GetParam(name) → GetValue()
• Set parameter → param.SetValue(newValue)
• List all parameters → model.GetParameters().GetParams()
• Create parameter → model.AddParam()

Assembly

• Add component → Feature creation with FeatureType.FEATTYPE_COMPONENT
• Apply constraint → componentFeat.SetConstraints(constraints, path)
• List components → solid.ListFeaturesByType(true, FeatureType.FEATTYPE_COMPONENT)
• Get subassembly → componentFeat.GetModelDescr() → session.RetrieveModel()

Interactive Selection

• Select edges → SelectionOptions.AddFilterType(SelectionType.EDGE)
• Select surfaces → SelectionOptions.AddFilterType(SelectionType.SURFACE)
• Get selected geometry → selection.GetSelectionItem(i) → process

Drawing

• Create view → sheet.CreateGeneralView(modelRef, viewData)
• Add note/dimension → sheet.CreateGeneralNote(position, text)
• Export/print → Drawing-specific APIs
• Get sheets → drawing.GetDrawingSheets()

Best Practices

1. Always use try-catch - All Jlink operations throw jxthrowable
2. Validate model type before specific operations (part vs assembly vs drawing)
3. Regenerate after changes - model.Regenerate() for feature/parameter changes
4. Check references validity - Geometry handles may become invalid after regen
5. Batch operations - Group model open/close for efficiency
6. Session reuse - Don't create new sessions; reuse GetCurrentSessionWithCompatibility()
7. Clear resources - Free large collections/selections after use
8. Log operations - Essential for debugging batch/async processes
9. Handle missing features - Wrap feature access in try-catch
10. Test with actual model - Jlink behavior varies by Creo configuration

Reference Files

For detailed information, see:

• jlink-session.md - Session creation, lifecycle, compatibility modes
• jlink-models.md - Model operations (open, create, save, properties)
• jlink-features.md - Feature creation, types, dimension manipulation
• jlink-parameters.md - Parameter access, modification, validation
• jlink-assembly.md - Assembly operations, constraints, components
• jlink-drawing.md - Drawing automation, views, sheets, export
• jlink-selection.md - Interactive selection, geometry types, filters
• jlink-patterns.md - Complete end-to-end workflow patterns
• jlink-error-handling.md - Exception strategies, recovery, logging
• jlink-performance.md - Optimization techniques, caching, async patterns

Installation & Setup

Prerequisites:

• Creo 4.0+ with J-Link/OTK selected during installation
• Java 21+ JDK for Creo 12.4+ (class file version 65.0)
• IDE: Eclipse, IntelliJ, or VS Code

CLASSPATH configuration (Creo 12.4+):

${CREO_HOME}/Common Files/text/java/otk.jar
${CREO_HOME}/Common Files/text/java/pfcasync.jar

CLASSPATH configuration (Creo 4.0-11.x):

${CREO_HOME}/Common Files/otk_java_free/*.jar

Application registration (jlink.txt):

DESCRIPTION=MyApp
STARTUP=DLL
JAVA_MAIN_CLASS=com.mycompany.MyApp
JLINK_VERSION=11.0
CLASSPATH=MyApp.jar

Common Use Cases

Batch Model Modification:

1. Get session
2. For each model: RetrieveModel() → modify parameters → Regenerate() → Save()

Assembly Generation from Data:

1. Create base assembly
2. For each component: AddFeature(COMPONENT) → ApplyConstraints()
3. Save assembly

Feature Extraction for CAM:

1. Get model
2. Iterate features by type
3. Extract geometry references
4. Generate NC code or CNC path data

Parameter-Driven Design:

1. Get session
2. Modify model parameters
3. Regenerate model
4. Extract modified geometry
5. Generate drawings/exports

UI Integration:

1. Create UICommand
2. Register in menu/toolbar
3. Handle selection via SelectionListener
4. Apply changes to model

Creo 12.4 API Quick Reference

Verified Methods (from JAR analysis)

Interface	Method	Returns	Description
Session	GetCurrentDirectory()	String	Current working dir
Session	GetActiveModel()	Model	Current active model
Session	RetrieveModel(ModelDescriptor)	Model	Open model
Model	GetFullName()	String	Full model path
Model	GetFileName()	String	File name only
Model	GetType()	ModelType	MDL_PART/MDL_ASSEMBLY
Model	ListParams()	Parameters	All parameters
Solid	ListFeaturesByType(Boolean, FeatureType)	Features	Get features
Solid	GetFeatureByName(String)	Feature	Get single feature
Solid	GetPrincipalUnits()	UnitSystem	Unit system
Feature	GetName()	String	Feature name
Feature	GetFeatType()	FeatureType	Feature type
Feature	GetStatus()	FeatureStatus	SUPPRESSED/ACTIVE/etc
Feature	ListSubItems(ModelItemType)	ModelItems	Get dimensions etc
Feature	ListChildren()	Features	Dependent features
BaseDimension	GetDimValue()	double	Dimension value
BaseDimension	SetDimValue(double)	void	Set dimension
ComponentFeat	GetModelDescr()	ModelDescriptor	Component model
Parameter	GetValue()	ParamValue	Parameter value
ParamValue	GetDoubleValue()	Double	Numeric value
ParamValue	GetStringValue()	String	String value

Non-Existent Methods (Common Mistakes)

Wrong Method	Correct Alternative
session.IsAlive()	Try-catch GetCurrentDirectory()
session.GetWorkingDirectory()	GetCurrentDirectory()
session.UISetComputeMode()	Not available in Creo 12.4
model.GetModelName()	GetFullName() or GetFileName()
feat.GetSuppressed()	GetStatus() == FEAT_SUPPRESSED
feat.GetFailed()	GetStatus() == FEAT_UNREGENERATED
feat.ListDimensions()	ListSubItems(ITEM_DIMENSION)
dim.GetValue()	GetDimValue() (BaseDimension)
compFeat.GetModelDescriptor()	GetModelDescr()
model.GetUnitsystem()	Solid.GetPrincipalUnits()

Unresolved Questions

• Async connection best practices for distributed teams
• Performance optimization for large assemblies (100+ components)
• Integration patterns with SmartAssembly scripting workflow