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HOUDINI TOOL: Folder-Based File Importer

Writer's picture: Pavel ZosimPavel Zosim

The Folder-Based File Importer is a custom Houdini Digital Asset (HDA) designed to streamline the process of importing multiple files from folders directly into Houdini.


Original Local Rotation Orientation
Original Local Rotation Orientation

Checking and changing the Local Scale and Orientation of Geometries is Made Easier with This Tool
Checking and changing the Local Scale and Orientation of Geometries is Made Easier with This Tool


Technical Insights

  1. Batch Importing with Subfolder Scanning

    • The tool can scan directories recursively, including subfolders, to locate and import files with user-specified extensions.

    • It uses multithreading (ThreadPoolExecutor) to speed up folder traversal, ensuring smooth performance even with deeply nested directories.

  2. Dynamic File Management

    • Users can enable or disable specific file formats (e.g., .obj, .fbx) through simple checkbox parameters.

    • The tool dynamically updates Houdini's Multiparm Block with the discovered files, providing a clear and organized list within the interface.

  3. Error Handling and Feedback

    • Robust error handling ensures users are informed of invalid paths, permission issues, or unsupported formats through both console messages and pop-up alerts.

    • The log_message and log_error functions centralize logging, improving maintainability and debugging.

  4. Parallel Processing

    • By using parallel processing for scanning subfolders, the tool minimizes bottlenecks when dealing with large or complex directory structures.

  5. Customizable Interface

    • Parameters like geometry scaling, rotation, and object margin allow users to fine-tune how imported assets are displayed and adjusted in the Houdini scene.

    • Metadata display options include toggling file names and attributes, which are particularly useful for managing large datasets.


Development Process and Design Choices

  1. Folder Scanning Logic

    • The script includes a flexible scan_folder function that supports both recursive and non-recursive file discovery.

    • By using Python's os module (scandir and walk), the tool ensures compatibility across different operating systems.

  2. Multithreading for Performance

    • The integration of ThreadPoolExecutor allows for concurrent scanning of subfolders, significantly reducing the time required to process directories with numerous subdirectories.

    • This approach balances workload across multiple threads, making the tool efficient even for extensive data imports.

  3. User Experience Enhancements

    • The script uses Houdini's UI components (hou.ui.displayMessage) to provide immediate feedback, making the tool intuitive for both beginners and advanced users.

    • Parameters are cached and reused during execution, improving script performance and reducing overhead.

  4. Scalable Architecture

    • The use of a mapping (extension_mapping) for file formats makes it easy to extend support for additional file types in the future.

    • Modular functions, such as import_files_from_folder and refresh_import, encapsulate specific tasks, adhering to clean coding principles.


Performance Comparison

In a real-world project test, the Folder-Based File Importer showed an execution time of 2.396s, while the standard File Merge SOP took 2.625s.

In this scenario, I selected 3 .obj files with a total of 1,387,781 polygons. The comparison demonstrates the efficiency of the Folder-Based File Importer, which streamlines the process by automating file selection and filtering compared to the manual approach of the File Merge SOP.
In this scenario, I selected 3 .obj files with a total of 1,387,781 polygons. The comparison demonstrates the efficiency of the Folder-Based File Importer, which streamlines the process by automating file selection and filtering compared to the manual approach of the File Merge SOP.

Key Differences

  • File Merge SOP:

    • Requires manual selection of files.

    • Suitable for small datasets but becomes slow and inconvenient when dealing with large file sets or nested folders.

  • Folder-Based File Importer:

    • Automatically scans folders and subdirectories.

    • Supports file format filtering, ignoring unnecessary data.

    • Speeds up the import process and reduces manual tasks, saving significant time for the user.


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