Step 1: Import Geometry

The geometry model defines the spatial locations of measurement points and the wireframe connectivity used to visualize mode shapes. A well-prepared geometry is essential for meaningful mode shape animation and validation.

Supported File Formats

Importing a Geometry File

1. Click Import Geometry in the toolbar or press Ctrl+G.
2. Select the geometry file from the file browser. The format is detected automatically from the file extension.
3. The 3D viewport displays the imported geometry with point labels. Use the mouse to orbit (left-drag), pan (middle-drag), and zoom (scroll wheel).
4. Verify that point positions and labels match your physical measurement setup.

Measurement Point Setup

Each measurement point represents a physical sensor location on the structure. Points are defined by:

Adding Points Manually

1. Right-click in the 3D viewport and select Add Point.
2. Enter the X, Y, Z coordinates and an optional label.
3. The new point appears in both the 3D view and the point list panel.

Editing Point Properties

Select a point in the 3D view or list panel, then modify its properties in the Properties pane on the right. Changes are reflected immediately in the viewport.

Skeleton / Wireframe Editing

The skeleton (wireframe) defines how points are connected visually. It does not affect the modal analysis computation but is critical for interpreting mode shapes.

Connecting Points

1. Select the first point by clicking it in the 3D view.
2. Hold Ctrl and click the second point.
3. Right-click and select Connect Points, or press C.
4. A wireframe edge is drawn between the two points.

Deleting Edges

1. Click on an edge to select it (the edge highlights in yellow).
2. Press Delete or right-click and select Delete Edge.

Auto-Connect

Use Edit > Auto-Connect to generate a skeleton automatically based on proximity. Set the maximum distance threshold to control connectivity density.

Show / Hide Controls

The toolbar provides toggles for controlling the 3D viewport display:

Coordinate System

V-Listen uses a right-handed Cartesian coordinate system. When importing geometry from external sources, verify that the axis orientation matches your measurement coordinate system. Use Edit > Transform to rotate, scale, or translate the geometry if needed.

Status Bar

The status bar at the bottom of the geometry view displays real-time information during import and editing:

• Point Count: Total number of measurement points loaded.
• Edge Count: Total number of wireframe connections.
• Surface Triangles: Number of triangles in the surface mesh (if loaded).
• Import Status: Progress indicator during file loading.

Format-Specific Notes

HMPL Files

The HMPL format is V-Listen's native geometry format. It stores point coordinates, labels, DOF directions, and full skeleton connectivity in a single file. HMPL files also support embedded metadata such as coordinate units and creation date.

• Point labels are displayed as dot-style markers in the 3D view.
• V-Listen searches for an associated STL file in the same directory and up to two parent directories. If found, the surface mesh is loaded automatically.
• If no surface mesh is found, a notification is shown in the status bar. The analysis proceeds with wireframe-only visualization.

UFF Geometry

Universal File Format geometry uses Dataset Type 15 (nodes) and Dataset Type 82 (trace lines). When importing UFF geometry:

• Ensure the file contains both node and trace-line datasets for complete wireframe import.
• Coordinate system definitions (Dataset Type 2420) are recognized and applied automatically.
• If only nodes are present (no trace lines), the geometry will appear as a point cloud without wireframe connections.

STL and OBJ Files

Surface mesh formats (STL, OBJ) define the structural surface but do not inherently contain measurement point definitions. When using these formats:

• Measurement points must be added manually or imported from a separate point list file.
• Use Edit > Snap Points to Surface to project manually placed points onto the nearest surface triangle.
• Both ASCII and binary STL formats are supported.

Best Practices

• Use consistent point numbering between your geometry file and channel-DOF mapping in Step 2.
• Keep the skeleton simple — connect only physically adjacent points to avoid misleading mode shape visualizations.
• For large structures, use labels that encode location (e.g., "FL_01" for front-left point 1) to simplify DOF mapping.
• Save your geometry as HMPL after editing so that skeleton connectivity is preserved for future sessions.
• Verify units before importing: coordinates must be in meters for correct scaling. Use the Scale transform to convert from millimeters if necessary.

Related Topics

• EMA Overview
• Import Test Data (Step 2)
• Mode Shape Animation