# VectorPaint three-blade front views: rotate copies instead of mirroring blades
Language: en
Canonical: [VectorPaint three-blade front views: rotate copies instead of mirroring blades]()
中文：[中文 HTML]()
English: [English HTML]()
Published: 2026-11-13T00:00:00+08:00
Modified: 2026-11-13T09:43:51+08:00
Author: Bison
Check three matching blades around one centre at 120-degree intervals, preserving hub occlusion and declared view direction.
English translation of the [Chinese original](), translated on 2026-11-13. Original publication dates, attribution, code and version notes are retained.
Draw an invented three-blade propeller front-view icon with matching handedness about one hub. A flat silhouette cannot establish real blade twist, speed or thrust direction. All rotations are drawing transformations, not aerodynamic analysis or a three-dimensional propeller designer in VectorPaint.
## Declare which face is being viewed
On a 1200×1200 canvas place hub O and declare “viewed from the illustrated front face”. The [NASA propeller explanation]() reminds us that real blades have sections and twist. This icon abstracts root-to-hub attachment and arrangement about an axis. Separate hub, blade original, copies, checking circle and labels, without engine or airflow arrows. A declared clockwise diagram direction explains transformation only; it does not infer thrust from an invented outline.
## Preserve an asymmetric bend in the original blade
Draw one long blade above O, bending slightly right, with narrow root, rounded tip and distinguishable left/right edges. Use few nodes and avoid a perfectly symmetric teardrop that would conceal a reflection error. Extend the root inside the hub as an occluded portion; omit elaborate twist marks and highlights initially. A tip distance of 400 pixels is an icon proportion, not a real propeller radius. Hide the hub and trace one closed continuous blade rather than disconnected pieces.
## Use the same O for all three directions
Draw three rays through O, separated by 120 degrees and totalling 360. With available numeric rotation, rotate one copy by 120 and a fresh original copy by 240. Otherwise place against rays and label approximation. Rotating around each blade’s own bounding-box centre without returning its root to O creates three separate centres. Inspect roots before tips, then compare tip distances against one checking circle so the common pivot has not silently changed.
## Keep handedness under rotation
For each blade, mentally align root-to-tip direction upward and compare the bulging side and tip bend. Rotations change global orientation without swapping the blade’s local sides. Do not horizontally flip one copy and vertically flip another to save work: reflections can produce similar-looking blades with mixed handedness. Use actual copy/rotation controls rather than an invented automatic propeller array. Retain the blade original so later edits can produce consistent new copies.
## Let the hub cover roots without losing their identity
Place the hub in front of roots, large enough to clarify the centre without consuming half a blade or exposing detached roots. In an audit copy, hiding it should reveal three roots extending into the same central region, not one growing from another blade’s middle. Concentric hub faces are decorative, and lettering or screw details must not become a fourth blade. Keep shading consistent. Validate three-blade structure with decoration hidden before restoring necessary detail.
## Compare a labelled reflected control without performance claims
In a separate control, reflect only one blade and mark the same local side on all three. Reorient each mentally to the original: the reflected blade’s mark switches sides, distinguishing reflection from a changed angle. This does not demonstrate failure of actual equipment without three-dimensional sections, materials or operating conditions. Label valid and incorrect versions and keep the error out of delivery. Preserve the other blades and hub so the comparison isolates one transformation.
## Troubleshoot tip radii and false counts in exports
Open a PNG, count three blades at reduced size, then enlarge roots to check the shared hub. A shorter tip radius suggests separate scaling or an incorrect pivot; identical copies should not differ without explanation. Visible checking rays on transparency are guides to hide, not motion trails. Six apparent blades call for checking duplicates or audit marks. Open SVG or PDF before reporting their text and occlusion behaviour; successful saving alone does not establish identical rendering everywhere.
## Reopen and verify centre, shape and transformation record
Save, leave and reopen the source. O remains the common reference, with recorded rotations of 120/240 degrees or explicitly approximate placement and no reflected copy. Open delivery output and inspect three blades, hub, negative space and viewpoint label, with guides hidden and original recoverable. A changed blade shape requires all copies to be updated, not just the top one. Acceptance means another reader can distinguish a shape-preserving rotation from a handedness-changing reflection; real rotation, thrust, efficiency and strength remain outside this flat icon.
## Related tutorials and sources
[VectorPaint translation and reflection: check each vertex coordinate and orientation](), [VectorPaint sixfold rosettes: audit rotational symmetry around one centre]().
Checked on November 13, 2026: VectorPaint public version 1.0.8, requiring iOS / iPadOS 17.0 or later. Scope follows the [official App Store]() and [Apple public lookup](). Manual exercises use controls actually available in your installed version; external calculations, written records and diagrams imply no built-in automatic analysis. No step-by-step physical-device, private-file or all-export-environment testing is claimed.