Table of Contents

Workflow: Geometry Validation

This workflow covers the suite of tools for validating machining geometry after simulation, including collision detection, geometry difference comparison, defect scanning, and flying piece removal.

flowchart TD
    Simulate["Run simulation"]
    Collision["Collision detection"]
    Diff["Geometry difference comparison"]
    Defect["Geometry defect scanning"]
    FlyPiece["Flying piece removal"]

    Simulate --> Collision
    Simulate --> Diff
    Simulate --> Defect
    Simulate --> FlyPiece

1. Collision Detection

Collision detection monitors whether the tool, holder, or spindle collides with the workpiece, fixture, or machine during simulation. Enable it before running the simulation.

Script Commands

EnableCollisionDetection = true;
EnablePauseOnCollision = false;  // set true to pause on collision
Property Description
EnableCollisionDetection Enables collision checking during simulation
EnablePauseOnCollision Pauses execution when a collision is detected

Combined with Pause on Failure

EnablePauseOnFailure provides a broader pause-on-error mechanism:

EnablePauseOnFailure = true;
EnableCollisionDetection = true;
PlayNcFile("NC/file1.nc");  // pauses if a collision occurs

GUI Operation

Enable collision detection in the main options panel before simulation.

Tip

Collision detection adds computation overhead. For exploratory simulations where speed matters, you can disable it and re-enable for final validation.

2. Geometry Difference Comparison

The Diff command compares the simulated workpiece shape against a target (design) shape to identify over-cut and under-cut regions.

Script Command

Diff(<DetectionRadius_mm>);

Detection Radius is the surface extension distance for the target shape. Deviations beyond this distance are not computed. Larger values take longer.

Diff(1);  // detection radius = 1 mm

Interpreting Results

After comparison, the workpiece surface is color-coded:

  • Green: Within tolerance
  • Red (positive): Over-cut exceeding the threshold
  • Blue (positive): Under-cut exceeding the threshold
Note

The path index on the workpiece surface is invalidated after running Diff. If you need to inspect individual step paths, do so before calling Diff.

Case Study: Reciprocating Slope Interference

CAM-generated NC code may contain subtle errors that are invisible without geometric comparison. Common issues found through Diff:

Issue Description
Right-angle wall under-cut Under-cut near walls where target geometry has sharp corners
Inconsistent Z plunging Over-cut from inconsistent Z values in reciprocating plunge regions
Insufficient radius clearance Under-cut at reciprocating edges where the tool hasn't moved out by its radius
Zebra-pattern under-cut Under-cut stripes from excessive reciprocating path spacing
Tip

Without software comparison, these issues can only be discovered after physical machining, significantly impacting precision manufacturing.

3. Geometry Defect Scanning

Geometry defect scanning helps debug abnormal workpiece or tool geometry. This is typically used only when geometry construction problems are suspected.

ScanRuntimeGeomInfDefect

ScanRuntimeGeomInfDefect scans for infinite edge cut defects in the runtime geometry. After scanning, defect areas are rendered with colored markers.

ScanRuntimeGeomInfDefect();

Return values:

  • true — defects detected
  • false — no defects
  • null — unable to execute (e.g., workpiece does not exist)

Workflow: Scan Before Simulation

ScanRuntimeGeomInfDefect();
Pause();                    // visually inspect defects
ClearDefectDisplayee();     // clear markers
PlayNcFile("NC/file1.nc");

ClearDefectDisplayee

ClearDefectDisplayee removes defect markers from the workpiece:

ClearDefectDisplayee();
Note

Defect markers are automatically cleared when the workpiece is reloaded or the runtime geometry is reset. During workpiece initialization, if construction defects are detected, markers are automatically displayed.

4. Flying Piece Removal

During five-axis cutting, small disconnected residual material fragments (“flying pieces”) may appear. Use RemoveFlyPiece to clean them up.

Script Command

RemoveFlyPiece();
Tip

Run RemoveFlyPiece after simulation and before geometry export (WriteRuntimeGeomToStl) to produce a clean output.

Combined Validation Script Example

// Configure and run simulation with collision detection
EnableCollisionDetection = true;
EnablePauseOnCollision = false;
EnablePhysics = true;
MachiningResolution_mm = 0.125;

PlayNcFile("NC/file1.nc");

// Remove any flying pieces
RemoveFlyPiece();

// Compare against target geometry (1 mm detection radius)
Diff(1);

// Scan for geometry defects
var hasDefects = ScanRuntimeGeomInfDefect();
if (hasDefects == true)
{
    WarningMessage("Geometry defects detected");
}

// Export final geometry
WriteRuntimeGeomToStl("Output/final.stl");
WriteStepFiles("Output/[NcName].step.csv");

See Also