Forge Viewer加载多模型时内存溢出问题咨询

Hey Bandu, let's break down your questions one by one based on my hands-on experience with Autodesk Viewer:

1. Preventing Viewer from Generating More Geometry Before Memory Runs Out #

• Batch Loading with Memory Monitoring: Instead of loading all 14 models at once, split them into smaller batches. After each batch finishes loading, check the browser's memory usage (use performance.memory for Chrome-based browsers, note you may need to enable the enable-experimental-web-platform-features flag) or track the Viewer's internal memory metrics. If usage hits a predefined threshold, pause loading and let the Viewer garbage collect unused resources before proceeding with the next batch.
• Optimize Geometry Loading Parameters: When calling loadDocumentNode, pass geometryParams to reduce upfront geometry load:
  • Use lod: true to load lower-detail level-of-detail models first, cutting down initial polygon count.
  • Enable skipHiddenFaces: true to skip geometry marked as hidden in the Navisworks file.
  • Set generateConsolidationGeometry: false if you don't need consolidated geometry (this saves significant memory for large model sets).
• Cancel Pending Loads: Listen to the Autodesk.Viewing.GEOMETRY_LOADED_EVENT, and if memory usage crosses your threshold, call viewer.cancelLoad() to halt any pending model loads immediately.

2. Viewing Total Statistics Across All Models with DebugTools #

The default NOP_VIEWER.initDebugTools() only shows stats for the active model, but you can easily aggregate totals across all loaded models with a quick script:

• Run this snippet in your browser's console to get combined polygon/vertex counts:

  let totalTriangles = 0;
  let totalVertices = 0;
  viewer.modelQueue().getModels().forEach(model => {
    const stats = model.getGeometryStatistics();
    if (stats) {
      totalTriangles += stats.triangleCount;
      totalVertices += stats.vertexCount;
    }
  });
  console.log(`Total Triangles: ${totalTriangles}, Total Vertices: ${totalVertices}`);
  

• If you want this integrated into the DebugTools panel, you can modify the extension's code to loop through all models instead of just the active one. Alternatively, build a tiny custom extension that adds a "Total Stats" tab to the existing DebugTools interface.

3. Alternative Ways to Count Polygons Across Loaded Models #

• Per-Model Stat Aggregation: As mentioned above, every loaded model has a getGeometryStatistics() method that returns detailed counts (triangles, vertices, etc.). Aggregating these values across all models gives you an accurate total.
• Incremental Tracking with Load Events: Listen to the Autodesk.Viewing.MODEL_LOADED_EVENT to track totals as each model finishes loading:

  let runningTriangleTotal = 0;
  viewer.addEventListener(Autodesk.Viewing.MODEL_LOADED_EVENT, (event) => {
    const model = event.model;
    const stats = model.getGeometryStatistics();
    runningTriangleTotal += stats.triangleCount;
    console.log(`Loaded ${model.name} | Total triangles so far: ${runningTriangleTotal}`);
  });
  

• Viewer Internal Memory Manager: The Viewer's viewer.impl.memoryManager holds internal memory-related metrics (note: this is an undocumented API, so use it cautiously as it may change in future versions) that can give you additional context on geometry memory usage.

内容的提问来源于stack exchange，提问作者Bandu W