MODULE 08 / DIGITAL WORKSHOP
Read the BDX-R assembly
Inspect the original STEP assembly, identify one component carefully, and begin a traceable part and fastener register. Learn what CAD validation can and cannot establish.
By the end, you can…
- Trace a component to a specific source revision and assembly location.
- Distinguish manufactured parts, purchased parts and viewing geometry.
- Record geometry defects and missing interface information accurately.
Install & explore CAD
Sketch to solid
Start with provenance
The audited CAD source is BDX-R V1.step from revision e63b081d379d0f10707dd11cea4e8cf788e8b9d8 of BDX-R-CAD. The filename is a label, not proof of the physical revision shown in the video. Preserve the downloaded file and make a working copy for inspection. Record the source link and revision in your part notes.
A STEP assembly can arrive as multiple objects, compounds or nested structures depending on import settings and exporter behavior. The original designer’s names and feature history may not survive. Do not treat a generic tree label or object number as a verified manufacturing part number. Build a mapping using shape, position, neighboring components and dimensions.
Separate three kinds of geometry
Some shapes represent parts you will manufacture, some represent purchased hardware, and some exist mainly to show an envelope or appearance. A motor-shaped STL may help render the joint without containing the exact mounting or internal details required to manufacture anything. A battery envelope can matter greatly for balance even when its cosmetic geometry is simple.
Make a register with a tentative name, source object identity, assembly location, dimensions, quantity, manufacturing category, confidence and unresolved questions. Put “unknown” in a field when evidence is insufficient. Two similar covers may be handed left/right parts rather than duplicates; confirm before multiplying quantities.
Geometry validity is one specific question
Our independent CAD import found 119 solids, with seven failing the geometry validator: indices 30, 42, 50, 65, 90, 95 and 101 in that import. FreeCAD can number or group them differently. Match a suspect by position and shape before assigning the audit’s index. The fact that every solid could be tessellated for viewing does not mean each original solid was valid.
A geometry check examines mathematical consistency. It does not establish strength, fatigue life, hole fit, material grade or suitable print orientation. A successful automatic repair can also change geometry, so inspect dimensions and interfaces afterward. The generic repair tried during the audit did not validate those seven solids; keep them unresolved rather than presenting a red-highlighted picture as a repair.
Read the load path and the interface
Ask how force travels from a foot through the ankle, leg and hip into the torso. Note which surfaces locate a part and which fasteners clamp it. For a screw, diameter alone is insufficient: length under the head, thread pitch, head style, material/grade, washer use and engagement all affect the joint. A rendered screw does not automatically reveal these specifications.
Kayden’s video describes replacing failed printed hip-roll connectors with aluminum and using an aluminum head base plate. Treat that as a cue to resolve the reinforced design and machining details. It is not permission to print a critical connector from an older mesh, nor a complete machining drawing specifying alloy, thickness and tolerances.
WORDS YOU NOW KNOW
- Provenance
- The source and revision history that establishes where a file or claim came from.
- Load path
- The route forces take through parts and connections.
- BOM
- A bill of materials: an identified, quantified list of components needed for a specified build.
- Tolerance
- The permitted variation in a specified dimension or geometric relationship.
YOUR CALL
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Primary references for this module. Use the version and hardware revision named in the lesson.
Pinned BDX-R CADKayden’s build and mechanical revisionsFreeCAD geometry checkingBDX-R description assets