# VectorPaint paired-gear diagrams: face teeth toward gaps and mark opposite rotation

Language: en
Canonical: [VectorPaint paired-gear diagrams: face teeth toward gaps and mark opposite rotation](<https://allluckly.cn/en/guides/vectorpaint-paired-gear-contact-diagram/>)
中文：[中文 HTML](<https://allluckly.cn/guides/vectorpaint-paired-gear-contact-diagram/>)
English: [English HTML](<https://allluckly.cn/en/guides/vectorpaint-paired-gear-contact-diagram/>)
Published: 2026-11-08T00:00:00+08:00
Modified: 2026-11-08T09:34:15+08:00
Author: Bison

Make a static illustration of equal external gears, distinguishing teeth, gaps, contact region and direction arrows without promising manufacture or interference-free operation.

English translation of the [Chinese original](<https://allluckly.cn/guides/vectorpaint-paired-gear-contact-diagram/>), translated on 2026-11-08. Original publication dates, attribution, code and version notes are retained.

Two toothed circles placed together do not necessarily explain external meshing. Tooth tips meeting tooth tips and arrows pointing the same way can miscommunicate the relationship. Make a static conceptual illustration with original simplified teeth, checking tooth-to-gap placement. This is not involute gear design, and appearance does not guarantee continuously operable physical parts.

## Separate centre references from tooth outlines

Create a landscape canvas with two equal pale reference circles, centres on one horizontal line, labelled A and B. Divide each into twelve equal directions, thirty degrees apart. Use a visible rotation-angle field if available and verify it; otherwise check manually against separate sector references without assuming a hidden array command. The reference circles arrange teeth and do not automatically constitute physical pitch circles. Keep centres and a centre-joining line before decorative holes, and record “equal wheels, twelve teeth, static illustration” in an external checklist.

## Complete alternating teeth and gaps on one wheel

Start wheel A with one short, clear trapezoidal tooth, narrower at the tip than the root, and arrange teeth along all twelve directions. Leave gaps between neighbours rather than overlapping trapezoids into a continuous rim. Combine separate shapes or create one closed outline, checking actual closure instead of treating white fill as a transparent opening. Count twelve teeth and twelve intervening gaps at enlarged size, then inspect merging at reduced size. The invented tooth profile supplies no module, pressure angle or machining dimensions; correct count does not establish a manufacturable profile.

## Offset the second wheel by half a tooth interval

Duplicate A as B, retaining size and tooth count, and offset its tooth directions by fifteen degrees, half the thirty-degree interval. Where A has a rightward tooth, B should present a left-facing gap rather than another opposing tip. Adjust centre distance for a readable contact region; touching outer bounding boxes alone does not define meshing. Inspect both sides for obvious tooth-root and gap conflicts, reducing illustrative tooth depth or changing spacing as needed. Do not describe this manual visual adjustment as completed gear-interference analysis.

## Enlarge the contact region separately

Select one representative tooth-to-gap relationship and connect it to an enlarged inset using a leader. Reproduce the same A tooth and B gap rather than inventing an opposite arrangement. Retain A/B labels or different patterns, with colour only supplementary. If opening a gap for legibility, label it “gap exaggerated for illustration”, not a physical contact dimension. Leaders indicate a region and are not transmission shafts. Improve an unreadable main composition rather than using one correct inset to validate an incorrect overall mesh.

## Use opposite rotation arrows for external meshing

Put a clockwise curved arrow above A and a counterclockwise arrow above B, with arrowheads matching their curves. Write both directions in words first and check the drawn arrows rather than inferring direction from their side of the wheel. This describes the direction relationship of ideal external meshing, without guarantees about physical speed, torque or efficiency, and does not extend to an internal ring gear. Keep arrows separate from gear groups so repositioning a wheel does not rotate explanatory arrows into ambiguity. Resolve clockwise direction against an ordinary clock before drawing if needed.

## Make a tooth-to-tooth counterexample

Duplicate a small comparison retaining centres and outline sizes, but change B’s phase so opposing tips meet, and label it an incorrect counterexample. Preserve the original correct illustration. Identify relative tooth placement as the fault, not colour or arrow weight, and do not infer physical breakage from the wrong drawing. After restoring the half-interval offset, recheck all twelve directions and the representative contact region. If only the inset was corrected while the main view still collides, repair the main view rather than handing off contradictory local and overall relationships.

## Distinguish holes, outlines and references before export

For optional shaft holes, centre each hole representation and identify whether it is a true opening or merely background-coloured illustration. Change background colour to distinguish them; a white circle is not automatically transparent. Hide manually drawn centre and sector references, save the editable source and export a PNG at viewing size. Independently count teeth, read arrows and identify the inset target. If narrow gaps merge into black edges, reduce stroke weight or enlarge the drawing rather than deleting a tooth or two and changing the twelve-tooth specification.

## Conclude only what this drawing establishes

The final check should establish each tooth count, which component presents a tooth or gap at contact, opposite arrow directions and a matching inset. For collisions, inspect phase and spacing first; for count errors, inspect missing duplicates before redrawing every outline. A genuinely moving mechanism requires separate tooth-profile and mechanical design, not extrapolation from this schematic. Preserve the source, counterexample and output so readers can distinguish static explanatory accuracy from automatic gear design, simulation or certification.

## Related tutorials and sources

[VectorPaint sixfold rosettes: audit rotational symmetry around one centre](<https://allluckly.cn/en/guides/vectorpaint-sixfold-window-rosette/>), [VectorPaint detail callouts: match enlarged areas to their source](<https://allluckly.cn/en/guides/vectorpaint-detail-callout/>).

Sources checked on November 8, 2026: VectorPaint public version 1.0.8, requiring iOS / iPadOS 17.0 or later. Capability scope follows the [official App Store description](<https://apps.apple.com/cn/app/id1587272880>) and [Apple public version lookup](<https://itunes.apple.com/lookup?id=1587272880&country=cn>). This original exercise can be performed independently; use the controls in your installed version. It does not claim completed physical-device, private-file or all-export-environment testing. Manual checks and external records are not newly promised automatic analysis features.