人工智能生成3D废料的尸检
An autopsy of AI-generated 3D slop

原始链接: https://aircada.com/blog/ai-vs-human-3d-ecommerce

## AI 与 3D 建模:尚未成熟 尽管人工智能取得了进步,但为电商生成可用的 3D 模型仍然是一个重大挑战。虽然人工智能可以快速生成乍一看还不错的模型,但仔细检查会发现关键缺陷阻碍了实际应用。最近对人工智能生成的匹克球拍和手工制作版本进行的比较凸显了这些问题。 人工智能模型存在“三角形汤”问题——混乱、无序的几何结构,使得即使是简单的编辑也变得极其困难和耗时,通常需要完全重建。纹理通常是低分辨率的“幻觉”,缺乏对材质的理解,导致烘焙光照和难以辨认的细节。虽然人工智能生成的文件尺寸较小,但这归因于低效的几何结构,而非优化的质量。 目前,人工智能 3D 生成优先考虑速度和文件大小,而不是可用性。这导致模型不适合产品配置器,在产品配置器中,视觉保真度和可编辑性对于建立客户信任至关重要。除非人工智能能够可靠地生成干净的拓扑结构和正确的材质分离,否则“节省时间”的说法是一种谬论——修复人工智能生成的模型通常比从头开始创建它们花费*更多*时间。目前,人工干预仍然是高质量、生产就绪的 3D 资产的关键。

最近Hacker News上出现了一场关于AI生成3D模型的质量讨论,起因是一篇名为“AI生成3D垃圾的剖析”的文章。核心批评在于,目前的AI在创建适用于专业应用(如电商)的模型时存在困难,它更注重视觉吸引力(“足够好”的表面),而非结构完整性和实际可用性。 一位评论员强调了“内在代理”的概念,认为模型缺乏对其自身几何结构的根本理解,导致仔细检查时出现问题。另一些人则认为这项技术*正在*改进,较新的模型能够生成更清晰的拓扑结构和纹理,并且现有输出可以通过诸如减面工具之类的工具进行优化——类似于摄影测量技术的演变。 这场争论触及了“生成噪音”与“真实创作”之间的区别,以及超越表面光鲜的批判性评估的必要性。具有讽刺意味的是,这场讨论本身是由AI生成的文本促成的。
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原文

"Why aren't you using AI to generate your 3D models?"

Humans are starting to nail the art of AI slop identification in text, images, and video. But what about 3D? We create product configurators for e-commerce brands, and we've been asked many times why we're not using AI to generate the product models we use.

While LLMs can write code and diffusion models can win art competitions, the 3D generation landscape remains extremely... bumpy.

These generated assets feature a deceptive level of "good enough" at a glance, but suffer a complete breakdown of utility upon closer inspection. We recently worked with the American Pickleball League brand to create a paddle customizer.

For AI shits and giggles, we decided to compare an AI-generated model with our handcrafted version. Below is a 3D view of both assets. Can you spot the difference?

What about now?

Below is the reference image we fed to the AI.

2D Reference Image of Carbon Fiber Paddle

Side by side comparison.

Comparison of AI-generated 3D model vs Handcrafted model

Analyzing the 3D Artifacts

After running it through Trellis (one of the leading open source image-to-3D model generators) and comparing it against the handcrafted pickleball paddle our internal team created, I was able to group the design patterns based on their actual usability.

Trellis generated the model in about 8 seconds, which felt fast. The model was only ~1mb, which felt small! Maybe this could work! Perhaps the customer buying their next pickleball paddle won't be able to tell the difference!

But when you peel back the onion, it starts to get messy.

There are clear clusters composed of the exact same artifacts found in almost all current generative 3D models: wobbly silhouettes, illegible text, and impossibly bad UV maps.

Have a closer look at the wireframes

Wireframe comparison of AI-generated 3D model vs Handcrafted model

Vertically, the AI models move from "chaotic noise" to "slightly smoothed noise," but never to actual structure. Horizontally, the textures go from "hallucinated gibberish" to "baked-in lighting."

Interestingly, the AI pickleball paddle seems to avoid straight lines entirely.

Top down rendered comparison showing wobbly AI vs symmetrical handcrafted

This differs drastically in behavior from the handcrafted model, which inherently understands that a manufactured object requires symmetry. This suggests that generative 3D is relatively unique in its concentration of unusable, uneditable "slop geometry."

Consistency also appears to be a myth in 3D generation. When looking at multiple generations from the exact same image, it's clear that the model just guesses wildly. Below is a sample of three different AI attempts side-by-side with the handcrafted handle.

This leads us to our next critical question: why?


Why AI 3D Generation Fails eCommerce Standards

To avoid getting extremely technical, here are the 3 leading reasons why the AI model is technically "lightweight" (1MB) but practically "heavy" (unusable).

1. The Topology Trap: Triangle Soup

Handcrafted 3D relies on "edge flow," which are lines of geometry that naturally follow the contours of the object. This allows for smooth reflections and easy editing. AI models generate meshes using "isosurface extraction" or similar volume-to-mesh techniques. This results in what the industry calls triangle soup.

  • Look at the first image (AI): The triangles are scattered randomly, like shattered glass.
  • Look at the second image (Human): The triangles are organized in logical, structural quads.

If a client asks, "Can you make the handle slightly longer?", on the human model, I can select a loop of polygons and pull. The edit is done in 10 seconds.

On the AI model, I cannot. There are no loops. I would have to sculpt it like clay, destroying the texture in the process. It is actually faster to rebuild the entire model from scratch than to try and fix the AI's topology.

2. The Texture Hallucination

The most damning evidence is in the details. The AI sees pixels in the source image and projects them onto the 3D shape, but it possesses absolutely zero understanding of materials.

The AI (Left): The grip tape is a low-resolution smear. The branding text ("APL PRO") has been melted into an illegible blue blob. The lighting is "baked in," meaning if you rotate the paddle, the shadows don't move. It looks like a PlayStation 2 game texture.

The Human (Right): The grip tape has a PBR (Physically Based Rendering) normal map applied, meaning the bumps interact with light natively in the 3D viewer. The text is crisp geometry or a high-resolution decal.

We should also talk about the UV maps, which become nearly unusable. When you unwrap the 3D model to look at the raw texture file, you get this:

The fully generated texture from the AI looks like a big soup of random, terrible quality pixels that literally needs to be thrown out. There are no logical seams, making it impossible for an artist to open this in Photoshop and swap out a logo or fix a color code.

3. The "Fake Efficiency" Metric

There is a misconception that AI 3D is "bloated." Models like Trellis do indeed output small meshes, which is good on paper. Actually, the AI model output a file that was around 1MB. Our handcrafted model is 800KB.

Our hand-crafted mesh actually has a lot more vertices. So the AI is comparable in size, right? Somewhat... but in efficiency, not even close.

The AI's 1MB is spent on useless, chaotic triangles that define a wobbly, asymmetric shape.

The human's 800KB is spent on smart, dense geometry placed exactly where it's needed, paired with high-quality, editable texture maps.

It is not about the file size; it is about the quality per kilobyte. The AI gives you 1MB of trash. The human gives you 800KB of a production-ready e-commerce product.


What Does This Mean for E-Commerce 3D Pipelines?

It means that the human touch is still very much required. A good 3D modeler models intuitively, understanding where to place geometry for clean edge flow and how to create clean UV maps that can easily be modified.

The AI model on the other hand attempts to reduce the geometry to keep the file size low. But because it doesn't intuitively understand the shape, it removes geometry from important structural places (like the edge of the paddle) and leaves geometry in completely useless places.

The result is a silhouette that looks inherently lumpy. In e-commerce, trust is visual. If the digital product looks lumpy and cheap, the customer assumes the physical product is low quality.

The Reality of the "Time-Saving" Illusion:

If you use an AI model, you might think you are saving 4 hours of initial modeling time. However:

  • You cannot fix the texture to match brand guidelines.
  • You cannot easily adjust the shape for iterations.
  • You cannot animate it properly due to bad edge flow.
  • It looks demonstrably "cheap" in a standard web viewer.

To fix these glaring issues, a 3D artist has to "retopologize" (manually trace over) the entire AI model. This salvage process actually takes longer than just modeling the object from scratch because the artist is constantly fighting against bad geometry.

The Takeaway: A human touch is mandatory... for now.

Until AI models can natively output clean topology and separated PBR materials (roughness, metalness, normal maps) instead of just "colored geometry," they are effectively just 3D clip art.

Are they useful for background assets that will never be looked at up close? Maybe. Are they useful for selling a high-end, $200 physical product in a 3D product configurator? Absolutely not.

But as is seeming to be the norm with AI, a few years from now this post may not have aged well.

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