AP 242 – Model-based 3D engineering
Geometry with product and manufacturing information (PMI) such as tolerances and fits in a neutral format – independent of the CAD system, archivable and exchangeable with partners.
Engineering Systems
How we engineer
A plant of this complexity does not emerge from individual drawings. We have developed our own engineering tools and workflows that connect requirements, design and manufacturing in a closed loop.
- 01Trace KitRequirements and traceability across three layers – with evidence, drift detection and feedback.
- 02CAD & Geometry NodesOur own parametric CAD system in which every operation is a node.
- 03PMIDimensions, tolerances, datums and surfaces as semantic information on the 3D model.
- 04STEP AP 242 / AP 238Standard-compliant data all the way to manufacturing – .step and .stepnc.
Requirements engineering
3-Layer Closed-Loop Engineering
Requirements, components, documents and boundary conditions form one shared graph. Every decision has an origin, evidence and a timestamp.
- Layer 1
System
Overall goals, boundary conditions and system requirements of the plant – e.g. output, site, permitting. This is where planning, assignment and release take place.
- Layer 2
Plant integration
Interfaces and balances between assemblies: heat, material flows, pressures, temperatures. This is where we make sure the parts fit together.
- Layer 3
Assemblies
Detailed development of the individual components – lens field, optics, heat storage, DAC, electrolyser, synthesis – in parallel and with their own internal rounds.
The closed loop
- 01Plan
A planning round assigns tasks to the assemblies.
- 02Develop
The assemblies work in parallel and propose results.
- 03Release
The next planning round reviews and releases – with evidence for every node.
- 04Feedback
If a file or requirement changes, everything that depends on it is flagged as “suspect” across all layers until it is confirmed or revised.
Trace Kit
Every decision with an origin and evidence
The Trace Kit is our own tool for requirements management and traceability. It implements the 3-layer closed-loop approach technically: as a command-line tool, with automatic checks and a viewer that shows the project as a timeline.
Booking principle
As in accounting, every node has evidence – a file, decision, source or derivation. Anything without evidence is explicitly recorded as an assumption.
Drift detection
If a booked file changes, such as a CAD model, the system reports the deviation with node, file and timestamp.
Suspect links
Everything that depends on a changed node is flagged as “suspect” across all layers – until the owner confirms or revises it.
Immutable history
Released states are never overwritten but superseded by new versions. A hash-chained journal records every step.
CAD & Geometry Nodes
Our own CAD system – every operation is a node
To design our assemblies, we are developing SolidCraft, our own parametric CAD system. Every operation in the timeline – sketch, revolve, hole, pattern, assembly transfer – is also a node in the Geometry Nodes graph. This keeps every geometry traceable, parametric and automatable.
- Parametric models: dimensions as named parameters, changes propagate through the whole model
- Geometry Nodes: timeline and graph are two views of the same model, with swimlanes per body
- Constraint check: degrees of freedom of sketches and assemblies are evaluated continuously
- Scriptable and testable: models can be built by command and tested automatically
Product and Manufacturing Information
PMI: manufacturing information directly on the 3D model
Instead of a separate 2D drawing, our models carry all manufacturing information themselves – semantically, i.e. machine-readable, not just as graphics. Each annotation is a node of its own, bound to faces and edges of the model, and is written along with it on export to AP 242.
Dimensions and tolerances
Diameters, lengths, fits (e.g. H13) and limits – derived directly from geometry, with general tolerances according to ISO 2768.
Geometric tolerances
Flatness, perpendicularity, parallelism, runout and position according to ISO 1101 – including tolerance zone and material modifiers.
Datums and datum systems
Datums A and B according to ISO 5459. The system checks how many degrees of freedom a datum system constrains.
Surfaces and patterns
Roughness specifications such as Ra 6.3, theoretically exact dimensions for bolt circles and spacing, and notes on the tolerancing principle (ISO 8015).
Automatic standards check
A rule set reads the model and reports gaps before anything is manufactured: under-constrained sketches, missing datums, incomplete datum systems or position tolerances without theoretically exact dimensions. One click leads straight to the affected node.
Manufacturing data
All the way to the machine: AP 242 and AP 238 (STEP-NC)
We generate design and manufacturing data in open, standardised ISO 10303 (STEP) formats. This keeps information lossless and traceable from requirement to machine tool.
AP 238 – STEP-NC (.stepnc)
Instead of machine-specific G-code, the .stepnc file describes what is to be made: features, machining steps, tools and tolerances – linked to the geometry from AP 242.
One chain, one origin
Every manufacturing file is booked in the engineering graph and traceable to its requirements. If the design changes, the affected manufacturing file becomes visible automatically.
Export to AP 242
Semantic PMI (Part 47) and presentation (Part 46) are written together with the geometry and checked against the CAx-IF recommended practices.
