VectorPaint three-link chains: preserve openings and two interlocking joins

English translation of the Chinese original, translated on 2026-11-06. Original publication dates, attribution, code and version notes are retained.

Interlocking links are not simply overlapping rings: each pair needs different depth readings at its two crossings. Build a three-link static diagram, retaining complete ring sources before local visibility changes at two joins. This establishes neither metal joints nor load-bearing design and does not guarantee an exact physical chain pose from flat contours.

Make intersections occur only between neighbours

On a 1000 by 600 pixel canvas, arrange A, B and C left to right, overlapping neighbours but not A/C. Use unfilled stroked ellipses with equal weight so openings reveal the real background, not white cover ellipses. Example centres near x=200,420,640 with half-width 140 define layout only; keep vertical positions aligned. Verify two crossings per neighbour pair. Adjust shallow overlaps before shadows. Retain all three complete rings so every later local fragment traces to one source.

Write both pairs of crossing rules

For A/B, define B in front at the upper crossing and A at the lower. For B/C, define C in front above and B below. Number each crossing. Upper/lower refers to image position, not strength or welds. Temporary ring colours should identify both paths. Raising whole B affects multiple crossings and cannot satisfy all local rules. Do not change the rule to fit stacking while drawing. Retain a whole-object overlap version to compare exactly what segmentation repairs.

Construct local foreground sections from full sources

Create each small foreground arc along its full ring source, matching weight, curvature and endpoint direction and limiting it to that crossing. Use a verified mask or independent path rather than an assumed chain generator. Keep segment ends where no blunt cut is exposed and test continuity against changed backgrounds. Inspect coverage in a temporary contrasting colour, then restore it. Name source ring and join on each fragment so later weight changes include every independently maintained section.

Trace every ring to check opening and continuity

Trace A, then B and C, explaining continuation through occluded parts. Local patches must not fill an opening or abruptly thicken a ring. Hide shadows to ensure a foreground arc is not a floating fourth link. Both opposite depth readings per pair must work, not only the upper crossing. This establishes the intended interlocking image, not how physical closed metal links are assembled or what motion range they possess.

Recheck both joins when moving the middle link

Move B slightly upward in a copy and record the change, then inspect all four A/B and B/C crossings. Named fragments do not automatically follow B; check selection, then revise their ranges at new intersections. If A/C unexpectedly touch, decide whether that violates the original chain structure rather than silently adding a decorative third join. Preserve the original and exclude old fragments left behind after restoration. The middle object has dependencies on both sides; a pleasing position alone is not a complete edit.

Let colour and material support ring identity

After structure, choose one colour for all links or different colours for teaching. Establish one lighting direction instead of using arbitrary black patches to disguise gaps. Highlights follow ring curves and continue through foreground fragments without jumping surfaces. Inspect narrow openings and crossings when reduced, especially depth boundaries with identical colours. Simplify highlights in a separate version rather than removing essential occlusion. Metallic appearance is visual, not a claim about material, coating or durability.

Change backgrounds after export to detect fake holes

Retain full rings, local sections and rule diagrams. Inspect openings and seams on light/dark backgrounds after export. Transparency does not delete white covers; replace them or state the single-background limitation. Name three-link schematic, dimensions and revision and reopen it to exclude test colours and old arcs. Explain fragment ownership for editable delivery instead of handing over unexplained short paths. Real chain documentation needs physical structural verification; this illustration validates no loads, safety or manufacturing workflow.

Audit four crossings when the result looks merely stacked

For three pasted-looking rings, read foreground ownership at all crossings before adding dimensional gradients. Gaps need endpoint/source checks; filled holes need fill/patch checks. Recolour missed fragments by ring ownership rather than painting every object alike. After moving B, inspect both associated joins instead of only the obvious side. Repeat shadow-free, individual-ring, four-crossing and background checks so continuous objects, not explanatory text alone, establish the chain.