Forge Viewer 3.2.x版本Document.load在移动设备抛异常问题咨询

Alright, let's tackle this Forge Viewer 3.2.x issue you're facing—super tricky when the docs say a parameter is required but desktop browsers let you get away with skipping it, right? Let's break down what's happening and fix that mobile error.

First, let's recap the key details:

• You're using Autodesk.Viewing.Document.load(documentId, onSuccessCallback, onErrorCallback, accessControlProperties) where the official docs mark accessControlProperties as required.
• Skipping this parameter works fine on Chrome/Firefox desktop, but throws a TypeError: Cannot read property 'id' of null in mobile browsers, specifically in the PinchRecognizer logic.
• You can't switch to Viewer.loadDocument() because you need to load multiple models.

The error stack points directly to the viewer's gesture handler initialization on mobile—unlike desktop, mobile doesn't have a fallback for missing accessControlProperties, so the pinch recognition logic tries to read an id property from a null value.

Even without official examples for this parameter, we can construct a minimal valid object to satisfy the SDK's internal checks:

1. Quick Fix: Pass an Empty Object #

Start with the simplest approach—pass an empty object as the accessControlProperties parameter. Most SDKs handle empty configurations gracefully:

Autodesk.Viewing.Document.load(
  documentId,
  onSuccessCallback,
  onErrorCallback,
  {} // Empty access control config
);

2. More Robust Fix: Pass a Basic Config Object #

If the empty object doesn't work, explicitly include the id field (since the error is about reading 'id' of null) using your model's documentId:

const accessControlProps = {
  id: documentId, // Reuse your existing document ID here
  permissions: [] // Empty permissions array (adjust if you need specific access rules)
};

Autodesk.Viewing.Document.load(
  documentId,
  onSuccessCallback,
  onErrorCallback,
  accessControlProps
);

Why This Works #

The mobile gesture recognition module in Forge Viewer 3.2.x expects accessControlProperties to exist to initialize properly—desktop browsers have a hidden fallback that mobile doesn't. By passing even a minimal valid object, you prevent the SDK from trying to access properties on a null value, which resolves the pinch recognizer error.

内容的提问来源于stack exchange，提问作者Marion