Reproduction of ForgeCAD official 3D printer, keyboard, and dexterous hand cases: From benchmark GIF to parametric assembly

This chapter reproduction3dprinter-gpt52codex the official benchmark entries in the ForgeCAD public kit, and adds cases of the easily identifiable keyboard and the official movable dexterous hand from the video. The official 3D printer discloses the README table, prompt, and GIF results, while no corresponding source code is released from the public kit and assets repositories; the dexterous hand provides executable examplesexamples/mechanical/5-finger-robot-hand.forge.js. This chapter integrates the officially published animated GIFs, local rendering, and executable scripts into a single reproduction chain.

Figure 1: Official benchmark asset 3dprinter-gpt52codex-2026-02-13-14-36-06-v2.gif. The source is the LLM Benchmarks table in KoStard/forgecad-public-kitREADME, and the GIF file is hosted at KoStard/ForgeCAD-assets.

Why this chapter replaces the simple CAD bracket

The previous small bracket can illustrate the basic commands of ForgeCAD, but there is a significant difference in visual effect compared to the “complex assembly” described in the official documentation. The 3D printer example is more suitable for inclusion in the main README: it includes a gantry frame, a heating bed, X/Y/Z motion components, a print head, belts, wires, a material tray, and a control box. Readers can immediately understand that this is a complete mechatronic assembly, not just individual small parts. The keyboard in the video also serves as a second example: although it is not a robotic mechanism, it demonstrates ForgeCAD’s ability to represent dense repetitive structures, key arrays, housing angles, and local accent colors.

This is also closer to the abilities that robot tutorials should emphasize: instead of just creating a beautiful shell, the structural relationships are written as editable parameters. The print head X position, hot bed Y position, gantry Z height, and build volume dimensions are all written in the script parameters, allowing repeated modification and verification using the same source code later.

Official Entry Verification

The review command is as follows:

powershellgit clone https://github.com/KoStard/forgecad-public-kit.git ..\forgecad-public-kit
git clone https://github.com/KoStard/ForgeCAD-assets.git ..\ForgeCAD-assets

rg -n "3dprinter-gpt52codex|Make a detailed home 3D printer|ForgeCADBenchmark" ..\forgecad-public-kit\README.md
rg --files ..\forgecad-public-kit | rg -i "3dprinter|gpt52|version_2|forge\.js$"
rg --files ..\ForgeCAD-assets | rg -i "3dprinter|gpt52"

The machine’s conclusion is: The README of the public kit contains an official table row, and ForgeCAD-assets has a GIF. No public 3D printer .forge.js source files were found.

Local Clone Files

The reproduction-ready assets retained in this chapter are as follows:

Figure 2: The 3D printer assembly generated by this chapter’s replication script. The current version has aligned the main visual features with the official GIF: dark background, black frame, silver guide rails, blue heating bed, orange heating plate, cyan build volume box, red material tray in the upper right, and front control panel. It is not a line-by-line reproduction of the official source code, but an executable teaching version based on the same prompt. For pixel-level consistency, the official .forge.js, camera, and scene configuration must be available.

Environment Selection

This case does not require creating a new micromamba environment. ForgeCAD uses the Node.js/npm CLI, and local Chrome is used for rendering PNGs. It does not involve PyTorch, CUDA, or robot simulation dependencies, and does not consume GPU memory.

This machine’s reproduction environment:

Installation check:

powershellnode --version
npm --version
npx --yes forgecad@0.9.14 --version

Modeling Breakdown

The essence of these cases is AI-assisted CAD, rather than “images directly becoming CAD files”. The large model is responsible for converting natural language requirements, reference image observations, and engineering structures into .forge.js source code. Then, the ForgeCAD CLI executes this JavaScript/TypeScript script, leveraging its geometric modeling, Boolean, assembly, rendering, and export capabilities to generate viewable and exportable CAD geometry. In other words, .forge.js is the CAD source code, not the final CAD file; the ultimately exchangeable geometric results are still in files such as STEP, STL, and 3MF.

A more accurate process is:

mermaidflowchart LR
    A["自然语言需求 / 官方 prompt"] --> B["大模型生成或修改<br/>.forge.js 源码"]
    B --> C["ForgeCAD 执行脚本<br/>生成几何对象"]
    C --> D["forgecad run<br/>参数与脚本检查"]
    C --> E["forgecad render 3d<br/>截图 / GIF 帧"]
    C --> F["forgecad export<br/>STEP / STL / 3MF"]
    C --> G["forgecad check print<br/>制造边界检查"]

The local replication script breaks down the real functional modules of the 3D printer into multiple objects. All parts are not combined into a single union, as the readability of the official GIF depends heavily on local colors: the black frame, silver guide rails, blue heating bed, orange heating plate, cyan building volume frame, and red material trays all require separate retention of their materials.

Key parameters are concentrated at the beginning of the file:

javascriptconst headX = Param.number("Print Head X", 22, { min: -70, max: 70, unit: "mm" });
const bedY = Param.number("Print Bed Y", 12, { min: -45, max: 45, unit: "mm" });
const gantryZ = Param.number("Gantry Z", 128, { min: 70, max: 175, unit: "mm" });
const buildVolumeW = Param.number("Build Volume Width", 118, { min: 80, max: 150, unit: "mm" });
const buildVolumeD = Param.number("Build Volume Depth", 105, { min: 80, max: 135, unit: "mm" });

These parameters correspond to “params for controlling positions” in the official prompt. Readers of the tutorial can first modify only these values and observe how the print head, hot bed, and build volume change.

Run script

Enter the chapter directory:

powershellcd 21-机械臂和机器人设计/03ForgeCAD视觉逆向工程入门

Run ForgeCAD script:

powershellnpx --yes forgecad@0.9.14 run forgecad_3d_printer_demo.forge.js

Local machine results:

textObjects: 13
Verifications: 5 pass, 0 fail
Params: Frame Width=180, Frame Depth=150, Frame Height=210,
        Print Head X=22, Print Bed Y=12, Gantry Z=128,
        Build Volume Width=118, Build Volume Depth=105
Time: 563ms

The 5 verifications here include the overall width, depth, height, gantry height, and whether the print head is still inside the frame. These are not mechanical strength checks, but rather to prevent the model from being significantly distorted after parameter changes.

Multi-perspective Rendering

Rendering requires a Chrome path. The local command is as follows:

powershell$chrome = "C:\Program Files\Google\Chrome\Application\chrome.exe"

npx --yes forgecad@0.9.14 render 3d forgecad_3d_printer_demo.forge.js `
  --output assets/forgecad_3d_printer_iso.png `
  --camera 55:20 `
  --background "#242424" `
  --edges thin `
  --render-style classic `
  --chrome-path $chrome `
  --fresh-server `
  --port 5180

npx --yes forgecad@0.9.14 render 3d forgecad_3d_printer_demo.forge.js `
  --output assets/forgecad_3d_printer_front.png `
  --camera 70:18 `
  --background "#242424" `
  --edges thin `
  --render-style classic `
  --chrome-path $chrome `
  --fresh-server `
  --port 5181

npx --yes forgecad@0.9.14 render 3d forgecad_3d_printer_demo.forge.js `
  --output assets/forgecad_3d_printer_top.png `
  --camera 35:58 `
  --background "#242424" `
  --edges thin `
  --render-style classic `
  --chrome-path $chrome `
  --fresh-server `
  --port 5182

If you want to closely mimic the appearance of the official GIF, the key lies in these three points: using a dark background --background "#242424", using --render-style classic to maintain a more rigid CAD view texture, and using --camera 55:20 to include the red tray in the upper right corner and the front control box in the frame. The official sources do not disclose the original .forge.js, viewport scene, camera JSON, or material states, so it is impossible to ensure pixel-perfect consistency; for perfect alignment, you will need to obtain the source scripts from the official benchmark and the original viewport configuration.

Figure 3 shows the front view, which clearly displays the print head, hot bed, Z-axis optical axis, and control box.

Figure 4 shows a high top view that allows for the inspection of the positions of the rack, tray, belt, and hot bed.

The rendering output of the three images on this machine reports the same geometric boundary:

textSize:   224.0 x 224.0 x 229.0 mm
Volume: 449408.0 mm3
Bounds: [-102.0,-108.0,-3.0] -> [122.0,116.0,226.0]

Second case: Keyboard in the video

The keyboard in the video is well-suited to be added in the latter part of this chapter. Its focus is different from that of 3D printers: 3D printers emphasize complex assemblies and moving parts, while the keyboard focuses on regular arrays, shell tilt angles, specific accent colors, and the organization of numerous repeated parts. You can consider it as an “product appearance + parametric array” exercise for ForgeCAD.

The keyboard example uses a reproductionable modeling script as the main component: forgecad_keyboard_demo.forge.js. The video footage is used to help everyone observe the appearance features, while the results in the tutorial are generated by a local script. The script retains these adjustable parameters:

javascriptconst cols = Param.number("Columns", 12, { min: 8, max: 14, unit: "keys" });
const keyPitch = Param.number("Key Pitch", 15, { min: 12, max: 18, unit: "mm" });
const caseAngle = Param.number("Case Angle", 6, { min: 0, max: 12, unit: "deg" });
const knobOffset = Param.number("Knob Offset", 0, { min: -18, max: 18, unit: "mm" });
const accentKeyX = Param.number("Accent Key X", 2, { min: -4, max: 4, unit: "keys" });

Run keyboard model:

powershellnpx --yes forgecad@0.9.14 run forgecad_keyboard_demo.forge.js

Machine result:

textObjects: 5
Verifications: 4 pass, 0 fail
Params: Columns=12, Key Pitch=15, Case Angle=6, Knob Offset=0, Accent Key X=2
Time: 3127ms

Rendering command:

powershell$chrome = "C:\Program Files\Google\Chrome\Application\chrome.exe"

npx --yes forgecad@0.9.14 render 3d forgecad_keyboard_demo.forge.js `
  --output assets/forgecad_keyboard_iso.png `
  --camera 48:31 `
  --edges thin `
  --render-style studio `
  --chrome-path $chrome `
  --fresh-server `
  --port 5184

npx --yes forgecad@0.9.14 render 3d forgecad_keyboard_demo.forge.js `
  --output assets/forgecad_keyboard_low_angle.png `
  --camera 35:16 `
  --edges thin `
  --render-style studio `
  --chrome-path $chrome `
  --fresh-server `
  --port 5185

Figure 5: Isometric diagram of the keyboard. Focus on the key array, right-side knob, dark function key area, and red dot keys.

Figure 6: From a low angle, the thickness of the shell and the slightly raised keyboard angle are more easily visible.

Geometric boundaries of keyboard rendering output:

textSize:   214.0 x 119.9 x 33.9 mm
Volume: 327930.0 mm3
Bounds: [-107.0,-58.2,-6.1] -> [107.0,61.7,27.8]

Third case: Official dexterous hand

There is also a attractive movable dexterous hand GIF at the top of the ForgeCAD public kit. This case is more suitable for robotics than a keyboard, as it combines parameters, links, hinges, tendons and cables, and assembly objects all in the same .forge.js. We simply reuse the official example:

powershellCopy-Item ..\forgecad-public-kit\examples\mechanical\5-finger-robot-hand.forge.js `
  .\forgecad_robot_hand_publickit.forge.js
npx --yes forgecad@0.9.14 run forgecad_robot_hand_publickit.forge.js

Machine result:

textObjects: 76
Params: Scale=1, Finger Curl=40, Thumb Curl=35, Finger Spread=8
Time: 530ms

The core of “Active” is not the video player, but the parameter-driven posture. The following 4 frames modify Finger Curl, Thumb Curl, and Finger Spread respectively, and then a local GIF is synthesized:

powershellnpx --yes forgecad@0.9.14 render 3d forgecad_robot_hand_publickit.forge.js `
  --param "Finger Curl=45" `
  --param "Thumb Curl=38" `
  --param "Finger Spread=12" `
  --output assets/forgecad_robot_hand_02.png `
  --camera 42:28 `
  --background "#101318" `
  --edges thin `
  --render-style classic `
  --chrome-path $chrome

Figure 7: Parameter actions rendered using the official dexterous hand in local mode. You can think of it as “low-cost animation”: each frame is a real rendering of the same CAD script under different parameters, rather than manually cutting video.

The official animated images are also saved in this chapter for easy comparison:

Export CAD and print files

Export STEP:

powershellnpx --yes forgecad@0.9.14 export step forgecad_3d_printer_demo.forge.js `
  --output outputs/forgecad_3d_printer_demo.step

Export to STL:

powershellnpx --yes forgecad@0.9.14 export stl forgecad_3d_printer_demo.forge.js `
  --output outputs/forgecad_3d_printer_demo.stl

Export 3MF:

powershellnpx --yes forgecad@0.9.14 export 3mf forgecad_3d_printer_demo.forge.js `
  --output outputs/forgecad_3d_printer_demo.3mf

For the keyboard case, use the same command. Just replace the script name and output name with forgecad_keyboard_demo:

powershellnpx --yes forgecad@0.9.14 export step forgecad_keyboard_demo.forge.js `
  --output outputs/forgecad_keyboard_demo.step

npx --yes forgecad@0.9.14 export stl forgecad_keyboard_demo.forge.js `
  --output outputs/forgecad_keyboard_demo.stl

npx --yes forgecad@0.9.14 export 3mf forgecad_keyboard_demo.forge.js `
  --output outputs/forgecad_keyboard_demo.3mf

The dexterous hand can also export:

powershellnpx --yes forgecad@0.9.14 export step forgecad_robot_hand_publickit.forge.js `
  --output outputs/forgecad_robot_hand_publickit.step
npx --yes forgecad@0.9.14 export stl forgecad_robot_hand_publickit.forge.js `
  --output outputs/forgecad_robot_hand_publickit.stl
npx --yes forgecad@0.9.14 export 3mf forgecad_robot_hand_publickit.forge.js `
  --output outputs/forgecad_robot_hand_publickit.3mf

Output file size of this machine:

STEP is more suitable for importing into CAD software for further editing; STL/3MF is better suited for slicing software for previewing. This model is a teaching assembly, not an integrated part that can be printed directly.

How to understand the printing inspection results

Command:

powershellnpx --yes forgecad@0.9.14 check print forgecad_3d_printer_demo.forge.js

The machine result is FAIL. This is not a failure of the script execution, but rather the checker has indicated that the assembly display model is not suitable for direct FDM printing as a single unit:

textScene: 13 shape(s), 5128 triangle(s), bbox 224.0 x 224.0 x 229.0mm
PASS print.script.verifications: 5 script verification(s) passed.
FAIL print.geometry.collisions: 14 positive-volume collision(s) found.
FAIL print.fdm.wall-thickness: 1 object(s) have sampled wall area below 1.2mm.
WARN print.fdm.overhangs: 8 object(s) exceed 45deg unsupported overhang budget.
PASS print.mesh.validity: Meshes are closed and manifold at the sampled tolerance.

This is actually a teaching point: The official GIF shows the complex assembly capabilities, and it cannot be equated with “the entire printer can be printed at once”. If the goal is manufacturing, the frame, hot bed, guide rail supports, and print head housing need to be broken down into individual parts, and then wall thicknesses, chamfers, screw holes, tolerances, and support strategies must be added to each part.

The keyboard case will also receive a similar assembly inspection result:

textScene: 5 shape(s), 3056 triangle(s), bbox 214.0 x 119.9 x 33.9mm
PASS print.script.verifications: 4 script verification(s) passed.
FAIL print.geometry.collisions: 4 positive-volume collision(s) found.
PASS print.mesh.validity: Meshes are closed and manifold at the sampled tolerance.
FAIL print.fdm.wall-thickness: 1 object(s) have sampled wall area below 1.2mm.

The collisions here mainly occur when the keycap, casing, and function area are treated as a single assembly for inspection. If the real keyboard casing needs to be printed, the keycap, bottom shell, top cover, knob, and interface guard must be separated into individual parts.

Resource Usage and Time Consumption

This machine uses PowerShell to sample the Working Set of the cmd -> npm/npx -> node/chrome child process, and obtains an approximate peak value:

This level of manipulation is very light for ordinary laptops, and a 6GB GPU is not required. What truly consumes resources are more complex surfaces, Boolean operations, ultra-high-resolution meshes, or browser-side animation rendering.

Reproduction Boundary

1. The relationship between official assets and local replicas

This chapter uses two types of assets. The first type are official public assets, such as 3dprinter-gpt52codex GIFs, Robot Hand V2 GIFs, and the dexterous hand source code in the public kit; these are used to help everyone align with the official presentation. The second type are local teaching replication scripts, such as forgecad_3d_printer_demo.forge.js and forgecad_keyboard_demo.forge.js; these are used to enable people to actually complete the entire workflow from “requirement to source code, source code to CAD geometry, geometry to rendering, and export”.

Among them, the 3D printer benchmark currently provides GIFs and prompts, but no corresponding .forge.js is available. Therefore, this chapter presents a teaching version that aligns with the official visual features; the dexterous hand examples are directly taken from the official source code of the public kit.

2. How to let a large model generate a CAD-like model

It is more recommended to describe the requirements as “structured engineering tasks”, rather than just saying “generate a beautiful 3D printer”. For example:

text请用 ForgeCAD 编写一个参数化 CoreXY 风格 3D 打印机 .forge.js。
要求包含：黑色方框机架、蓝色热床、橙色加热板、银色 Z 轴导轨、
X 轴横梁、打印头、皮带、右上角红色料盘、前方控制盒和青色构建体积框。
暴露参数：Print Head X、Print Bed Y、Gantry Z、Build Volume Width、Build Volume Depth。
返回对象要按模块命名，便于 render 时保留材质颜色。
最后添加 bounding box 和参数范围验证。

After the large model generates a preliminary draft, do not treat the result as the final CAD file. The correct iteration method is: run forgecad run to check if the script is executable; render a PNG to verify the scale and perspective; export STEP/STL/3MF to check the exchange files; if necessary, report the error messages or screenshots to the large model so it can continue modifying .forge.js.

3. Does this process require micromamba?

No main line is required for this chapter. The ForgeCAD case only relies on Node.js/npm and Chrome rendering, and does not involve PyTorch, CUDA, or robot simulation environments. Only when combining ForgeCAD with Python CAD, simulation training, and robot learning algorithms into a single experimental project will the use of micromamba or conda environment isolation be considered.

4. Can these models be directly used in real manufacturing?

They cannot be directly used for the production of real machines. They are teaching-level parametric assembly tools used to demonstrate AI-assisted CAD, code-first CAD, complex structure breakdown, CLI verification, and file export. For real mechanical design, efforts must continue in terms of strength, stiffness, transmission, tolerance, procurement parts, assembly, material, and safety checks.

References

• ForgeCAD public kit: https://github.com/KoStard/forgecad-public-kit
• ForgeCAD assets: https://github.com/KoStard/ForgeCAD-assets
• ForgeCAD documents: https://forgecad.io/docs
• ForgeCAD npm package: https://www.npmjs.com/package/forgecad