Maker404 apps

Check your 3D model before you print it.

Upload an STL and get a clear list of what to fix before you print: does it fit, is anything floating, how much filament and time will it take. See your model on the printer bed in 3D.

Client-side only Offline after first load Same checks as the STL Viewer extension

Drop an STL here or click to browse

Binary and ASCII STL files are supported. Nothing leaves this device.

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Printer

Material Infill

15%

Filament cost ($/kg)

For teachers Build a preset classroom link

Max print time (minutes) Max cost ($)

Lock preset values Students cannot change locked fields

Shareable URL

This URL builder captures the current printer, limits, and lock settings. If you use a custom printer, the custom bed size is included too.

Upload an STL to start the check.

You’ll get a plain-language list of what to fix before printing, a 3D view of your model on the printer bed, and an estimate of weight, cost, and print time.

How the time estimate works

The app estimates filament from the model's volume: a solid shell about 0.85 mm thick around the surface (roughly two walls plus top and bottom layers), plus the infill percentage of the inside. That is why thin parts like keychains barely change with infill. Print time comes from that amount of plastic at a realistic flow rate for the printer, plus a few seconds per layer for layer changes and cooling, plus about 7 minutes of heat-up. It assumes 0.2 mm layers and is a rough range, not a slicer replacement.

How the checks work

Models are shown with Z pointing up, like Tinkercad and every slicer. The floating check splits the model into separate pieces and flags any piece that neither touches the bed nor overlaps a piece that does, so lettering inlaid in a plate is fine but a letter hovering above it is not. The surface check looks for open or doubled edges. Sizes assume millimetres.

About this tool

What it does. Upload an STL and this checker reports whether it fits the printer bed, whether any part is floating in the air, and whether the surface is closed. It estimates material weight and cost, gives a rough print time range, and shows your model in 3D on the printer bed, all before the file ever reaches a slicer.

Why it exists. In a classroom, a model that's too big for the bed or a print that quietly takes six hours is a wasted afternoon and a spool of filament nobody planned for. Catching that in ten seconds, before a student queues the job, saves both.

Built for the classroom specifically. The Teacher URL Builder lets a teacher pre-set the printer, a max print time, and a max cost, then lock those values into a shareable link. Students open that link, upload their model, and get an instant pass or fail against limits the teacher already decided, no manual checking required.