Peer-graded Assignment: Scanning同行评审作业：3D 扫描

The purpose of this assignment is to give you the opportunity to apply the concepts you have learned in this module and to discuss some of the key ideas of the module in your own words. Follow the instructions provided and respond to each question. This a required activity for this module.
本作业的目的是让你有机会应用在本模块中学到的概念，并用自己的话讨论模块中的关键思想。遵循提供的指示，回答每个问题。这是本模块的必做活动。

Scan an object(or yourself !) using any of the options available to you.
扫描一个物体（或你自己！）使用你可选的任何选项。

We recently learned (7th January 2017) that 123D Catch has been withdrawn from the app store, so if you are looking for an app, try http://www.trnio.com/tutorial/ for scanning with your iphone. For older phones, it maybe best to take pictures as recommended in the course video, and use the 'import images' feature in the trnio app. This way you can use your regular camera app and then import images into the app. Older devices (iPhone 5 and lower) sometimes crash when using the scanning function of the trnio app.
最近我们得知（2017 年 1 月 7 日）123D Catch 已被从应用商店下架，所以如果您在寻找应用，请尝试访问 http://www.trnio.com/tutorial/ 使用您的 iPhone 进行扫描。对于旧手机，最好按照课程视频中的建议拍照，并在 trnio 应用中使用“导入图片”功能。这样您可以使用常规相机应用，然后将图片导入到应用中。旧设备（iPhone 5 及以下）在使用 trnio 应用的扫描功能时有时会崩溃。

For Android try out http://scann3d.smartmobilevision.com/ .
为 Android 尝试访问 http://scann3d.smartmobilevision.com/。

Share the model using Sketchfab and submit the link. Answer the following discussion questions in 400-500 words(for all three questions together).
使用 Sketchfab 分享模型并提交链接。针对以下讨论问题回答，总字数在 400-500 字（三个问题合并回答）。

• Which type of 3D scanning method did you pick? How was your experience using it?
  你选择了哪种 3D 扫描方法？使用它的体验如何？
• Based on what you saw in the videos, when is it appropriate to use 3D scanning as a method? When does it not work so well?
  根据你在视频中看到的，何时使用 3D 扫描作为方法比较合适？何时效果不佳？

Sharing a public link is critical to this work and will be needed at each step. Use sketchfab to upload your design to share the link. Create a free account, Upload your model, and click publish. You should get a shareable link, which can be copied and pasted here.
分享公共链接对这项工作至关重要，每个步骤都需要。使用 sketchfab 上传你的设计以分享链接。创建免费账户，上传你的模型，然后点击发布。你应该获得一个可分享的链接，可以在此处复制粘贴。

Submit your answers to each of the questions based on the prompt provided on the My submission tab. Enter your answers directly in the spaces provided in the My submission tab. You may save a draft of your work as you go, and you can come back later to continue working on your draft. When you are finished working, click the Preview button, verify your identity, and then click Submit for review to submit the assignment.
提交您根据“我的提交”标签页上的提示提出的每个问题的答案。直接在“我的提交”标签页中提供的空白处输入您的答案。您可以在进行过程中保存草稿，稍后回来继续编辑草稿。完成工作后，点击“预览”按钮，验证您的身份，然后点击“提交审核”以提交作业。

Grading Criteria Overview 评分标准概述

You are required to evaluate the submissions of at least THREE of your peers based on the instructions and rubric provided. You may begin giving feedback to other students as soon as you submit your assignment; click the Review Your Peers page to begin. Feel free to provide additional reviews beyond the three required!
您需要根据提供的说明和评分标准评估至少三位同行的作品。您提交作业后即可开始对其他学生进行反馈；点击“审查你的同行”页面开始。请随意提供超出三个要求的额外评价！

This assignment is worth 5 points total. As you review your peers, points should be given only for correct/reasonable answers as specified in the rubric provided; incorrect/unreasonable answers get zero points.
这项作业总共 5 分。在评审同学时，只有符合评分标准中规定的正确/合理答案才能得分；错误/不合理答案不得分。

Recommendations for Fair Peer Review:
建议进行公平同行评审：

• The goal is not perfection, but practice. Please focus on the objective, quantitative aspects of the assignment.
  目标不是完美，而是练习。请专注于任务的客观、量化方面。

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导出3D模型的格式取决于你的用途，以下是USDZ、USDC和OBJ的对比分析：

1. USDZ（苹果生态友好）

• 适用于AR应用（苹果的ARKit）

• 无需额外解压，可以直接在iOS/macOS系统中查看

• 支持材质、动画、光照信息

• 不能直接编辑，适用于最终展示用途

2. USDC（多层USD格式，适用于编辑）

• 适用于复杂场景、多层结构的存储

• 适合在Pixar USD管线（如Maya、Houdini、Blender等）中编辑

• 比USDZ更灵活，可分层存储

• 适用于专业3D工作流，但不如USDZ直接支持苹果AR

3. OBJ（通用3D模型格式）

• 兼容性最高（几乎所有3D软件都支持）

• 只存几何数据（不支持材质、动画、光照）

• 适合用于建模软件（Blender、Maya、3ds Max等）进行二次编辑

• 体积较大，不适合AR直接展示

选择建议

• 如果是苹果AR展示（iOS/iPadOS） ➝ USDZ

• 如果要在Pixar USD管线中编辑（Maya、Houdini等） ➝ USDC

• 如果要在各种3D建模软件中使用和编辑 ➝ OBJ

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📎 Dole-6ff79553-d5a6-4406-a212-51b26a525675.usdz

我通过iOS商店中一个叫做3D扫描的app扫描了1个dole的3D菠萝汁罐头。这个app总共分3个步骤，先是让我圈定我要扫描的物品，然后围着这个罐头转了一圈，再让我把罐头倒过来再转一圈，最后再让我把罐头转到正面再扫一圈。有一个360度的进度条和颗粒渲染暗示我的扫描进度。最后大概3分钟我就导出了我的模型，支持USDZ、USDC和OBJ三种格式。

Response:

1. Which type of 3D scanning method did you pick? How was your experience using it?
I used a photogrammetry-based 3D scanning method through an iOS app called 3D Scanner. The process involved three main steps: first, I had to outline the object (a Dole pineapple juice can) on my phone screen. Then, I walked around the can while the app captured its shape from multiple angles. The app prompted me to flip the can upside down and scan it again, followed by a final scan of the upright position to ensure full coverage. A 360-degree progress bar and particle rendering provided real-time feedback on the scanning progress. The entire process took about 3 minutes, and I was able to export the model in USDZ, USDC, and OBJ formats.

My experience was surprisingly smooth and intuitive. The app’s step-by-step guidance made it easy to follow, even as a first-time user. The real-time feedback was particularly helpful, as it allowed me to adjust my movements to ensure complete coverage. However, I noticed that lighting and surface texture played a significant role in the quality of the scan. The shiny surface of the can caused some reflections, which slightly affected the accuracy of the model. Despite this, the final result was impressive, capturing the shape and details of the can with reasonable precision.

2. Based on what you saw in the videos, when is it appropriate to use 3D scanning as a method? When does it not work so well?
3D scanning is most appropriate when you need to capture the exact geometry and texture of a physical object for purposes such as replication, customization, or digital archiving. For example, it is ideal for creating 3D models of sculptures, artifacts, or industrial parts where precision is critical. It is also useful in fields like reverse engineering, where existing objects need to be analyzed or modified digitally. Additionally, 3D scanning is valuable in virtual reality (VR) and augmented reality (AR) applications, where realistic models are required to create immersive experiences.

However, 3D scanning may not work well in certain scenarios. For instance, shiny, reflective, or transparent surfaces can cause inaccuracies due to light reflections or refractions. Similarly, moving objects or those with complex, intricate details (e.g., fine hair or feathers) can be challenging to scan accurately. Additionally, 3D scanning requires adequate lighting and a controlled environment to produce high-quality results. In low-light conditions or cluttered spaces, the scan quality may degrade significantly.

3. Share the model using Sketchfab and submit the link.
https://skfb.ly/p9tuX

In conclusion, 3D scanning is a powerful tool for capturing real-world objects in digital form, but its effectiveness depends on the object’s characteristics and the scanning environment. My experience with the 3D Scanner app demonstrated how accessible and user-friendly this technology has become, making it a valuable resource for both professionals and hobbyists.

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