要计算全局偏移，可以使用Autodesk Forge的Model Derivative API和Viewer API。下面是一种解决方法的示例代码：

1. 使用Model Derivative API将CAD模型转换为SVF格式：

import requests

def translate_model(file_path):
    url = 'https://developer.api.autodesk.com/modelderivative/v2/designdata/job'

    headers = {
        'Content-Type': 'application/json',
        'Authorization': 'Bearer YOUR_ACCESS_TOKEN',
    }

    payload = {
        'input': {
            'urn': 'urn:adsk.objects:os.object:YOUR_BUCKET_KEY/' + file_path
        },
        'output': {
            'formats': [
                {
                    'type': 'svf',
                    'views': ['3d']
                }
            ]
        }
    }

    response = requests.post(url, headers=headers, json=payload)
    response.raise_for_status()

    job_id = response.json()['id']
    return job_id

2. 使用Model Derivative API获取转换后的模型属性：

import requests

def get_model_properties(urn):
    url = 'https://developer.api.autodesk.com/modelderivative/v2/designdata/' + urn + '/metadata'

    headers = {
        'Authorization': 'Bearer YOUR_ACCESS_TOKEN',
    }

    response = requests.get(url, headers=headers)
    response.raise_for_status()

    properties = response.json()
    return properties

3. 从模型属性中提取全局偏移：

def get_global_offset(properties):
    global_offset = properties['data']['metadata'][0]['globalOffset']
    return global_offset

4. 使用Viewer API加载模型并应用全局偏移：

function loadModel(urn, globalOffset) {
    const viewer = new Autodesk.Viewing.Viewer3D(document.getElementById('viewer'));

    Autodesk.Viewing.Initializer({ accessToken: 'YOUR_ACCESS_TOKEN' }, function () {
        viewer.start();

        const options = {
            sharedPropertyDbPath: urn + '/metadata/properties.sqlite',
            globalOffset: globalOffset
        };

        viewer.loadModel('urn:' + urn, options);
    });
}

请注意，以上示例代码只是一个简单的示例，实际使用时可能需要根据具体情况进行适当的修改和调整。