theofficeofnilsjohansson

3D Model & Drawing Management Procedure


Document No.	JDS-PRO-003
Revision	B
Date	2026-03-25
Status	APPROVED
Author	Nils Johansson

1. Purpose

This procedure defines how 3D models, engineering drawings, and related files are organised, named, stored, and tracked within JDS. Every modeling project — whether it’s a single part or a full assembly — follows the same structure so that files are always findable, traceable, and version-controlled.

2. Scope

Applies to all 3D modeling and drawing work, including:

Blender projects (.blend)
Shapr3D projects (.shapr)
build123d scripts (.py)
Exported files (STEP, 3MF, STL — mandatory standard set)
Reference images and sketches
Related documentation (DWG documents)

3. Folder Structure

3.1 Overview

Each modeling project gets its own folder under projects/3d-modeling/, named with its JDS drawing number:

projects/3d-modeling/
├── JDS-DWG-MEC-001_flange-adapter/    # One folder per project
│   ├── README.md                       # Project card (quick reference)
│   ├── source/                         # Source/working files
│   │   ├── flange-adapter.blend        # Blender file
│   │   ├── flange-adapter.shapr        # Shapr3D file
│   │   └── flange-adapter.py           # build123d script
│   ├── exports/                        # Exported output files (standard set)
│   │   ├── flange-adapter.step         # MANDATORY — CAD interchange
│   │   ├── flange-adapter.3mf          # MANDATORY — 3D printing (preferred)
│   │   ├── flange-adapter.stl          # MANDATORY — 3D printing (universal)
│   │   └── flange-adapter.glb          # Optional — web/presentation
│   ├── references/                     # Reference material
│   │   ├── sketch-001.jpg
│   │   └── datasheet.pdf
│   └── renders/                        # Screenshots and renders
│       └── final-render.png
│
├── JDS-DWG-STR-001_bracket-mount/     # Next project (Structural domain)
│   ├── README.md
│   ├── source/
│   ├── exports/
│   ├── references/
│   └── renders/
│
└── _shared-references/                 # Materials shared across projects
    ├── standard-fasteners.md
    └── material-properties.md

3.2 Key Rules

One folder per JDS drawing number. A project folder is created when a DWG number is assigned.
Folder name = JDS number (with domain) + short description. Example: JDS-DWG-MEC-001_flange-adapter/
Source files go in source/. These are the editable working files.
Exports go in exports/. These are the output files for fabrication, sharing, or viewing.
References go in references/. Sketches, datasheets, photos — anything used as input.
Renders go in renders/. Screenshots, final renders, preview images.
Every project has a README.md — the project card (see Section 5).

3.3 Shared References

The _shared-references/ folder (prefixed with underscore to sort to top) holds material that applies across multiple projects — standard fastener libraries, material property tables, common dimensions, etc.

4. File Naming

4.1 Source Files

Source files use descriptive lowercase names with hyphens:

part-name.blend
part-name.shapr
part-name.py

For multi-part projects or assemblies, use a prefix:

assembly-name_part-01-housing.blend
assembly-name_part-02-cover.blend
assembly-name_full-assembly.blend

4.2 Export Files

Exports match the source file name with the appropriate extension:

flange-adapter.step         # MANDATORY — CAD interchange
flange-adapter.3mf          # MANDATORY — 3D printing (preferred)
flange-adapter.stl          # MANDATORY — 3D printing (universal)
flange-adapter.glb          # Optional — web/presentation
flange-adapter_v2.step      # Variant — append version if needed

4.3 Mandatory Export Standard

Every 3D model project must export these three formats:

Format	Extension	Why it’s mandatory	Use case
STEP	`.step`	Preserves solid geometry. Editable in any CAD tool. Your insurance policy for future modifications.	CAD interchange, CNC machining, sharing with engineers
3MF	`.3mf`	Modern printing format. Carries units, materials, colour, and tolerances in one file.	3D printing (preferred by modern slicers)
STL	`.stl`	Universal mesh format. Every slicer and viewer reads it.	3D printing (universal fallback), quick sharing

Optional exports (add when relevant):

Format	Extension	When to include
glTF/GLB	`.gltf` / `.glb`	Web viewers, blog posts, presentations, AR/VR
OBJ	`.obj`	When specifically requested by a collaborator
PDF (2D)	`.pdf`	Dimensioned drawings for machine shops or documentation

Why STEP is critical: STL and 3MF are mesh formats — you cannot easily edit them later. STEP preserves the actual solid geometry, so you or anyone else can reopen it in Shapr3D, FreeCAD, or any CAD tool and modify the design. Always export STEP first.

4.4 Reference Files

References use descriptive names:

sketch-initial-concept.jpg
datasheet-dn50-flange.pdf
photo-site-measurement.jpg

5. Project Card (README.md)

Every project folder contains a README.md that acts as a quick-reference card. Use the template below:

# [Part/Assembly Name]

| | |
|---|---|
| **JDS No.** | JDS-DWG-[DOM]-[NNN] |
| **Rev** | A |
| **Date** | YYYY-MM-DD |
| **Status** | DRAFT / APPROVED |
| **Author** | Nils Johansson |

## Description
[What is this? What is it for? 2-3 sentences.]

## Key Dimensions
| Parameter | Value | Unit |
|-----------|-------|------|
| [Dimension] | [Value] | mm |

## Tools Used
- [ ] Blender
- [ ] Shapr3D
- [ ] build123d

## Source Files
| File | Tool | Description |
|------|------|-------------|
| source/[filename] | [Tool] | [What it contains] |

## Exports (mandatory standard set)
| File | Format | Purpose |
|------|--------|---------|
| exports/[filename].step | STEP | CAD interchange (editable) |
| exports/[filename].3mf | 3MF | 3D printing (preferred) |
| exports/[filename].stl | STL | 3D printing (universal) |

## Notes
[Design decisions, constraints, tolerances, material choices, etc.]

6. Workflow: Creating a New 3D Project

Step 1: Assign a DWG number

Check the Document Registry for the next available DWG number in your domain. Pick the engineering domain code (MEC, MAR, AUT, etc.) from the Numbering Standard.

Step 2: Create the project folder

mkdir -p projects/3d-modeling/JDS-DWG-MEC-001_short-name/{source,exports,references,renders}

Step 3: Create the project card

Copy the README template from Section 5 into the project folder and fill in the header.

Step 4: Do the work

Create your models in the source/ folder. Collect references in references/.

Step 5: Export the standard set

Export all three mandatory formats to exports/:

.step — CAD interchange (always first)
.3mf — 3D printing (preferred)
.stl — 3D printing (universal fallback)

Step 6: Register the document

Add the DWG entry to the Document Registry.

Step 7: Commit

Commit the project folder to the repository. Use a descriptive commit message:

Add JDS-DWG-MEC-001: Flange adapter DN50 — initial model

7. Revision Control for 3D Models

3D models follow the same revision control as other JDS documents (see JDS-PRO-002), with these additions:

7.1 What Counts as a Revision

Change	Action
Dimensions changed	New revision (update DWG document + re-export)
Material changed	New revision
New variant added	New revision OR new DWG number (see 7.2)
Cosmetic/render update only	Minor update (same revision, note in commit)
Bug fix in build123d script	New revision if output changes; minor if not

7.2 Variants vs. Revisions

Revision: The same part, improved or corrected. Same DWG number, next revision letter.
Variant: A different version of a part (e.g., different size, different mounting). Gets its own DWG number with a note referencing the original.

Example:

JDS-DWG-MEC-001  Flange Adapter DN50
JDS-DWG-MEC-002  Flange Adapter DN80 (variant of DWG-MEC-001)

7.3 Export on Every Revision

Whenever a source file is revised, re-export all output files. Old exports that don’t match the current source are misleading. The Git history preserves previous versions if needed.

8. Large Binary Files

8.1 Git Considerations

Binary files (.blend, .shapr, images, STL) don’t diff well in Git. Best practices:

Commit meaningful snapshots, not every auto-save
Write descriptive commit messages for binary changes since the diff won’t show what changed
For very large files (>50MB), consider using Git LFS (Large File Storage). This can be configured later if needed.

8.2 What to Commit

File type	Commit to Git?	Notes
.blend	Yes	Main working file
.blend1 / .blend2	No	Auto-backups (in .gitignore)
.shapr	Yes	Main working file
.py (build123d)	Yes	Source code — diffs perfectly
.step / .3mf / .stl	Yes	Mandatory export set
.glb / .obj	Yes	Optional exports when relevant
Reference images	Yes	Keep reasonable sizes (<5MB each)
Renders	Yes	Final renders only, not drafts

9. Quick Checklist: New 3D Project

DWG number with domain code assigned from registry
Project folder created: projects/3d-modeling/JDS-DWG-[DOM]-[NNN]_name/
Subfolders created: source/, exports/, references/, renders/
README.md project card filled in
Source files saved in source/
Mandatory exports generated: STEP + 3MF + STL in exports/
Document registry updated
Committed to repository with descriptive message

Revision History

Rev	Date	Author	Description
A	2026-03-25	Nils Johansson	Initial release
B	2026-03-25	Nils Johansson	Renamed JEDS to JDS. Added domain codes to folder naming. Added mandatory export standard (STEP + 3MF + STL).