v1.5.1

Fixes the Print checklist sometimes including students from the previously viewed class after switching classes without refreshing. The checklist now reads only the students that are showing.

v1.5.0

Adds an optional Print checklist and a settings popup. The 3D viewer itself is unchanged from 1.4.2. See CHANGELOG.md for full details.

Added

• Print checklist (off by default). A button on an assignment's Student work page that opens a one-page printable list of every student and their STL file, grouped by the colour in the file name (a ? marks a guess; a dropdown on each row changes it). Color and Student views, sort by first or last name, Print / Save as PDF.
• Settings popup behind the extension's toolbar icon. Switch on Print checklist there; an open Classroom tab reloads so the button appears. Under Advanced is an off-by-default Troubleshooting tool that copies an outline of a Classroom page with all text, names and file names removed.

Privacy and permissions

• New storage permission, used only to remember those two on/off switches. Chrome shows no new warning for it. Host permissions are unchanged.
• With the checklist switched on and its button clicked, the extension reads student names, submission status and attachment names from that page, in your browser only: held in memory in a tab you can close, never saved or sent anywhere. The privacy statements in the README and docs/privacy-policy.md are updated to say so.

Known limits

• The checklist depends on how Classroom lays out the Student work page. If Google changes it, it will say it couldn't find any students; the Troubleshooting tool helps repair that.
• Not on the Chrome Web Store yet. Install as an unpacked extension (below).

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

Already installed? Replace your folder with the new one and click the refresh icon on the extension card at chrome://extensions, then reload your Classroom tabs.

See the README for full usage instructions.

v1.4.2

Fixes false "Floating geometry detected" warnings. See CHANGELOG.md for full details.

Fixed

• The floating check no longer flags pieces that are embedded in the model. It used to warn about any separate piece that didn't reach the print bed, so lettering or artwork inlaid in a plate, and parts nested inside a body, were reported as floating even though they print fine. A piece now counts as floating only if it neither reaches the bed nor overlaps a piece that does. A letter hovering above a plate is still flagged.

Known limit

• The overlap test uses bounding boxes, so a part floating inside a hollow body, or in the empty corner of an L-shaped one, is not caught.

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

Already installed? Replace your folder with the new one and click the refresh icon on the extension card at chrome://extensions.

See the README for full usage instructions.

v1.4.1

Save PNG now names the file after the student's submission. See CHANGELOG.md for full details.

Changed

• Save PNG is named after the student's file. A submission called Cool Boat.stl saves as Cool Boat-screenshot.png instead of stl-preview.png every time, so feedback images no longer overwrite each other or need renaming. The name comes from the download's Content-Disposition header, falling back to an .stl link or on-page text, then to stl-preview-screenshot.png. Characters that aren't allowed in file names are stripped.

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

Already installed? Replace your folder with the new one and click the refresh icon on the extension card at chrome://extensions.

See the README for full usage instructions.

v1.4.0

Adds a PETG option and shows the floating-geometry check's status in the toolbar. See CHANGELOG.md for full details.

Added

• PLA / PETG selector next to the infill selector, shown in the Save PNG header
• Floating-check status in the toolbar: "Checking…", then "✓ No floating geometry" or the warning, with explicit "skipped" and "failed" states, so a missing warning always means the check passed

Changed

• The floating check runs just after the viewer opens instead of before it
• Its limit is raised from 200,000 to 1,000,000 triangles. It measures about 0.25 ms per 1,000 triangles, so large models like 3DBenchy were being skipped for no reason

Fixed

• The toolbar no longer pushes Save PNG and Close off-screen in narrower windows. The hint shrinks first, then the buttons wrap together

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

Already installed? Replace your folder with the new one and click the refresh icon on the extension card at chrome://extensions.

See the README for full usage instructions.

v1.3.0

Adds volume and estimated filament weight. See CHANGELOG.md for full details.

Added

• Volume and estimated weight in the toolbar and the Save PNG header, e.g. 67.2 cm³ · ~56.3 g
• Infill selector (10%–100%, default 20%) that adjusts the weight estimate. Weight assumes PLA (1.24 g/cm³) with about 1.2 mm of solid shell around the surface, so thin parts like keychains barely change with infill, as in a slicer. It's a rough guide, not a slicer's number, and assumes millimetre units and a watertight mesh.

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

Already installed? Replace your folder with the new one and click the refresh icon on the extension card at chrome://extensions.

See the README for full usage instructions.

v1.2.1

Bug-fix release. See CHANGELOG.md for full details.

Fixed

• Auto-orient showing tall models (lighthouses, figurines) on their side — Tinkercad's Z-up export convention is now the default "up" axis, instead of guessing from bounding-box thinness
• "Failed to fetch" when downloading from Google Drive directly (missing drive.usercontent.google.com permission)
• Download URL detection could grab a Google support link instead of the actual file
• Near-invisible toolbar hint text

Added

• Icon set (16/48/128px)

Changed

• Narrowed host_permissions to only the domains actually used

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

See the README for full usage instructions.

v1.2.0

Floating geometry detection, model dimensions, Reset View, and Save PNG — see CHANGELOG.md for full details.

Install (Developer Mode)

1. Download stl-viewer-extension.zip below and unzip it.
2. Go to chrome://extensions, enable Developer mode.
3. Click Load unpacked and select the unzipped stl-viewer-extension folder.

See the README for full usage instructions.