GemSim

Name: GemSim
Author: Xuezhong Wang

3D Gem Faceting Simulator

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🎨 Graphics & Design

Free

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Details

Released: August 25, 2026
Updated: November 7, 2026
Version: 1.3.56
Compatibility: iOS 18.7+
Age Rating: 4+
Size: 70.44MB
Devices: iPhone, iPad
Data updated: 2 days ago
Languages: American English

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Xuezhong Wang

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About

Design your gemstone before you cut it. GemSim is a free 3D gemstone faceting simulator for designing, visualizing, and refining gemstone cuts before touching a real stone. Whether you're learning faceting, exploring fantasy cuts, planning rough stones, or recreating published designs, GemSim brings powerful design tools to iPhone, iPad, and the web. INTERACTIVE 3D SIMULATION • Rotate, zoom, and inspect gemstones from any angle • See design changes instantly in 3D • Preview realistic gemstone renderings • Analyze light return, windowing, and head shadow NEW: FANTASY CUTTING Go beyond traditional faceting with creative cutting tools. • Create fantasy cuts using ball, cylinder, and V-groove cutters • Combine fantasy cuts with traditional facets • Adjust cutter positions and cutting depths • Visualize and experiment with unique patterns in 3D NEW: ROUGH PLANNING & AUTO-FIT Plan your cuts and make better use of valuable rough material. • Import 3D rough stone scans in STL, OBJ, or GLB format • Visualize rough stones and finished designs together • Move, rotate, and scale designs within the rough • Use Auto-Fit to find placements that fit inside the rough • Compare placements to maximize potential yield FACETING DESIGN EDITOR Create and refine designs with precise controls. • Add, edit, reorder, duplicate, and delete tiers • Control facet angles, depths, and indices • Create and reuse custom index sequences • Select meet points directly from the 3D model • Support fractional indices for advanced designs • Toggle tier visibility and undo changes FROST EDGE Create decorative frosted edges directly in 3D. • Select individual or symmetrical groups of edges • Adjust frost width for precise effects • Frost crown, pavilion, and girdle edges • Generate editable frost tiers automatically • Preview frosted facets in realistic rendering • Include frost details in printable diagrams DESIGN LIBRARY Explore thousands of classic and public gemstone designs. Search by shape, name, designer, or dimensions. Preview, load, and customize designs instantly. CLOUD STORAGE & SHARING Create a free account to save and share designs across devices. • Store up to 100 designs in the cloud • Share through public links or with specific users • Control View Only or View + Copy permissions • Manage access separately for each design An account is optional. Core features work without signing in, and local file storage remains available. IMPORT, EXPORT & PRINT • Save and open editable GemSim project files • Export gemstone designs as 3D models • Generate printable cutting diagrams and instructions • Work with local files without an account BUILT FOR GEM CUTTERS Whether you're a beginner, experienced faceter, hobbyist, student, or gemstone designer, GemSim lets you experiment with angles, proportions, fantasy cuts, frost patterns, and complete designs before cutting real stones. Make mistakes on the screen instead of on the dop. GemSim is free to use, with no subscription required to design, edit, or simulate gemstones. Start designing today and discover what's possible before you make the first cut.

What's New in GemSim

1.3.56

November 7, 2026

HELP AND MANUAL - Added the standalone GemSim manual with a screenshot for every section. - Help tutorials now open externally on YouTube and no longer embed a player. - Native apps exclude the static manual; it remains available on the web. - Manual updated for mirror controls, shape thumbnails, the 4:6 Geometry layout, the new labels, and matching Clockwise with the machine’s index-gear direction. - Help/Feedback display the build version instead of the hard-coded v0.0.0. AUTHENTICATION - Sign-in and account requests now time out after 10 seconds. - Sessions expire 24 hours after sign-in, with a five-minute expiry warning. - Added session-expiry handling in AuthControl, App, and PublicViewer, plus unit tests. GEOMETRY AND MIRRORING - Added Mirror Pavilion and Mirror Crown controls. Mirroring reflects tier indices across the top index, preserves fractional indices, and keeps each facet’s polished/frosted finish. - Mirror checkboxes are session-only and are not saved in design files. Opening a design resets them, and legacy mirror flags are stripped. - Index and Rough Size now share the full row at a 4:6 ratio, with responsive wrapping, a minimum Index width, reduced Rough Size padding, and Pavilion/Crown kept on one line. - Renamed Index to Index Gear and Reverse to Clockwise, and replaced the mirror icon with a Mirror label. - Decoupled mirroring from Clockwise and open tier edits: mirror controls stay enabled, and mirroring saves any open tier edit first. LIBRARY - Added 47 gem-outline thumbnails and a ShapeSelect component to the library shape picker. - Added unit and e2e coverage for thumbnail mapping and picker behavior. VERSIONING AND NATIVE BUILDS - package.json is now the single app version source. - Vite injects the web version; Help and Feedback read it. - Android Gradle reads package.json directly and derives versionCode as major * 10000 + minor * 100 + patch. - iOS uses version:sync to update MARKETING_VERSION and CURRENT_PROJECT_VERSION, with a CI version check. - Removed the old Android version.properties generator, tag-based Android version reader, and Netlify auto-version bump. - Fixed an iOS Swift package mismatch by keeping Capacitor at 8.5.0 to match the lockfile, with a guard test. - Added gitignore entries for Android release output and local Gradle toolchain files. - Releases in this range: 1.3.53, 1.3.54, and 1.3.56. SENTRY - Added Sentry monitoring for web and Capacitor. - Added the Sentry Vite plugin, CLI, React and Capacitor packages, native initialization, source-map upload support, Cocoa pinning, documentation, and tests. BEAUTY RENDER - Fixed missing Babylon Ray import that broke beauty-render drag rotation after moving the divider. - Added panel-size observation so the renderer resizes with the divider and keeps the correct aspect ratio. - Updated render e2e tests for the current Analyze tab and added coverage for resizing and orbit drag. GCS AND ASC IMPORT - GCS index_angle values are now converted directly to gear indices for crown and pavilion tiers. - ASC pavilion indices are mirrored before normalization to match the GCS/displayed order; crown, girdle, and table indices are unchanged. - GCS tier frosting attributes are supported. - GCS per-facet frosting intensity is supported; positive values such as 0.5 mark the facet frosted. - GCS XML parsing tolerates stray leading bytes before the XML root. The attached frost_export_test.gcs now opens and P3 imports as frosted. - Added regression tests for index conversion, tier/facet frosting, and XML prefix handling. OTHER FIXES - Fixed near-coincident crown cuts disappearing at C5, with a regression fixture and e2e test. - Fixed TypeScript 5.9 Buffer typings in the print worker, print client, and PDF generator.