# Explain 3D FREE: Understand how stuff works — user reviews > 7 indexed App Store user reviews of Explain 3D FREE by ePic design s.r.o., rated 2.00/5 from 5 ratings. - Source: https://appshunter.io/ios/app/explain-3d-free-understand-how-stuff-works/id968247111/reviews - App overview in markdown: https://appshunter.io/ios/app/explain-3d-free-understand-how-stuff-works/id968247111.md - Rating breakdown: 5★ 1 · 4★ 0 · 3★ 0 · 2★ 1 · 1★ 3 ## Most critical reviews (7 lowest-rated) ### 1/5 — Useless *2019-07-22* They waisted their time making a useless app,DON’T GET THE APP ### 1/5 — Contains ONE basic simulation *2018-09-24* Forces you to pay to see anything more than a boring 2-stroke engine. Just a carrot to try and trick people into buying more simulations ### 1/5 — Disappointing *2017-03-11* Don't bother unless you pay for the full version, there's only one simulation on the lite version. Just look it up on the internet. ### 1/5 — Inaccurate *2016-09-27* Tried the 4-stroke simulation to check it out, the flow of fuel and exhaust is poorly timed and would confuse someone entirely that doesn't already know how it works. Fuel appears to flow into the cylinder while the piston is compressing, and exhaust leaves when the fuel should be flowing in, while a vacuum is being formed. Doesn't instill confidence in the other simulations of things I don't fully grasp yet. ### 3/5 — Why is there 1 thing *2019-05-27* Jug ### 3/5 — Potential. Needs work *2016-04-17* Judging from the trial, the animation was good but then it went out of sync and didn't make sense (was wrong). Would be good if you can also slow the animation and click step by step. Needs more work ### 5/5 — New Content and update *2017-03-11* Please keep new stuff coming.. the prices are a little high though. --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-01.*