A visible equipment model is not automatically selectable: planning objects and hierarchy

Define selection with an actual user action

“All equipment must be selectable” leaves the boundary unclear. A usable requirement might say that clicking a pump housing, base or motor selects the same pump, while a maintenance view allows the motor to be selected separately. This identifies both the physical parts that must remain distinct and the business entity to which they belong. The number of mesh fragments is not a reliable measure of interaction scope.

One equipment item may contain several meshes, while one mesh may contain parts of multiple machines. Separating by material or disconnected geometry is a production operation, not recognition of equipment identity. Matching colors do not establish common ownership, and physically connected shapes do not necessarily belong to the same selectable item.

Keep three layers in the asset register

• Business object: a stable equipment identifier, short name, location and intended user action. This is the item reviewers should recognize.
• Geometric composition: the housings, supports and parts belonging to it, plus background elements that should not participate in selection.
• Delivery structure: the exported node or retrievable identifier, and the relationship that maps several parts back to one equipment item.

The hierarchy should support selection and maintenance, not turn every screw into a user-facing entry. A device group can clarify the boundary of an asset normally updated as a whole. Independently moving components should remain identifiable underneath it where the task requires that separation.

Distinguish asset defects from picking rules

If the authoring file cannot isolate a machine, investigate its geometry first. If it contains separate objects but the application always selects a guard in front, investigate the picking behavior. The official Three.js Raycaster documentation describes intersections carrying the hit object and being sorted by distance. The application still has to translate a geometric hit into the intended business selection. This reference was checked on October 6, 2026; verify behavior against the project's installed version.

These mechanisms do not mean that exporting any model again will make it usable. Welded geometry, lost identifiers or missing parts may require asset work. Transparent housings and background obstructions require the implementation and modeling teams to diagnose the result together rather than assuming all failures have the same cause.

Prove the structure on one difficult sample

1. Choose a sample containing an enclosure, attached parts and a neighboring machine. Mark exactly which visible pieces belong together.
2. Agree on hierarchy, stable identifiers and non-selectable background objects. Do not use a changing export sequence as the business identifier.
3. Export to the intended format and reopen it in the receiving environment. Hide, show and locate each item to detect merging or renaming.
4. Pick from several normal viewing angles and record expected versus actual equipment. Include close neighbors and partially obscured objects.
5. Replace the sample asset once and verify that the identifier relationship survives before extending production to the remaining scene.

Does a merged production line need rebuilding?

Not necessarily. Where equipment boundaries can still be recovered, assess selective separation and restructuring. For a limited presentation, an explicitly agreed proxy selection region may also be considered. If that region does not follow the real outline, document the risk of selecting a neighbor; it is not equivalent to precise picking of the model surface.

Deliver an object register, identifier mapping, hierarchy overview and verification result from the intended receiving environment. Live data binding, equipment status and information panels are separate application requirements. Identifiable assets make those features possible to specify, but their presence does not mean those features have already been implemented.

Attach a highlighted view to each business object in the register, so the recipient can distinguish a complete machine from one of its parts.

Mark the business objects that must be selected individually on one section of the line, then use the asset reuse assessment to identify necessary separation. The model and UI coordination guide connects those identities to screen actions. For 3D modeling services (Chinese), annotate the boundaries of whole machines, parts and groups instead of requesting an unspecified “interactive model.”