printsim

3D print simulator

The fanciest loading bar for your 3D prints.

Load the file you're printing, hit start when your printer does, and watch it build layer by layer from anywhere.

Runs entirely in your browser. Your file never leaves this device.

New here? Here's the deal

Lab printers like the Prusa MINI+ aren't on the network, so once you hit print, the only way to check on it is to walk back. printsim is a stand-in: give it the same file you gave the printer, tap Start when the printer starts, and it rebuilds the print in 3D in real time, with how long is left and when it'll be done.

  • Live 3D buildThe printer moves and the layers stack up as they print, from your dorm or class.
  • Timelapse firstScrub or play the whole print at up to 1000× before you commit an 8 hour print.
  • Spaghetti checkForgot supports? It flags what'll droop or fall, and shows it happening.
  • Close the tab, it's fineIt remembers the print. Come back later and it picks up where the printer should be.
  1. Load the same file you sent to the printer
  2. Start the sim the moment you press print
  3. Resync any time by typing the % on the printer's screen

Tuned for the Prusa MINI / MINI+ using Prusa's own firmware numbers. Other printers get a generic profile. Timing is an estimate, not a live feed.

What does the printer show?

The sim jumps to exactly that point in the file. Do this right before you walk away from the printer.

%
Time left on its screen (more precise)

When did it finish?

This is how printsim learns how fast this printer really is. Rough is fine.

Name this printer

Something you'll recognise at the lab. Each named printer learns its own speed.

Your prints

Running more than one printer? Each print gets its own page, so you can follow them all from here.

In the works

What's being built and fixed next. Still Prusa MINI+ first.

Up next

  • Topple and warp warningsTall, skinny parts can get knocked over by the MINI's moving bed, and big flat PETG or ABS parts lift at the corners. printsim will flag both and suggest a brim.
  • Snap to resyncPoint your phone at the printer's screen and it reads the % and time left for you. Runs on the phone, the photo never leaves it.
  • Risk coloursColour the model by what the support check thinks happens to each line: holds, sags, hangs or falls.
  • Laptop to phoneStarted the sim on a laptop? Scan a QR code and the same print carries on on your phone.
  • Status linkSend a friend a link with a live countdown to when your print is done. No account, no server.

Getting better

  • TimingOn some prints the sim trails the printer by 1 to 2%. Real timing runs at the Brandeis lab are tuning it.
  • More materialsPLA overhangs and bridges are now tuned from a real test print. PETG and PLA with the fan off are next.
  • Realistic spaghettiPlastic printed in mid-air gets dragged around by the nozzle into a loose rope. The sim still drops it in a tight pile.
  • A better failure demoThe "forgot its supports" sample got more honest and a lot less dramatic. It needs a part that truly starts in mid-air.
  • iPhone remindersThe "it's done" calendar link opens in Safari instead of the Home Screen app.

Maybe later

  • Heads-up alertsA ping a few minutes before the finish or a filament change.
  • More printersMK4, Core One and .gcode.3mf files, once the MINI+ is nailed.

Updated 16 Oct 2026

Get pinged when it's done

Adds calendar events with alerts, so your phone buzzes even with printsim closed.

Google Calendar

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