EnginPlot

A fast, dependency-free viewer for time-history data

Load RPC3, PLT, fstrm, or CSV files and see tens of millions of samples plotted instantly — no installer, no companion DLLs, just one .exe.

Designed by an engineer, for engineers.

EnginPlot showing twenty channels of automotive hilly-terrain data — a time-history plot above a power-spectral-density plot, with channel thumbnails on the left and a histogram panel on the right

Features

Reads what you already have

RPC3, PLT/SimCreator, fstrm/Moog Stream, and CSV — with automatic header and unit detection.

Time, frequency, and histogram views

Time-domain, PSD, and CSD plots — including CSD Matrix and CSD Overlaid modes — plus per-channel histograms.

CSD phase wrap control

Unwrap the phase, or choose a wrap range — ±180°, 0–360°, 0–720°, and more — on cross-spectral density plots.

Layouts that fit the data

Overlay every channel, stack them one per row, or group rows by engineering unit.

Automatic dual Y-axis

Channels spanning very different scales split cleanly onto a second, right-hand axis — no manual setup.

Zoom exactly where you point

Rectangle-zoom by dragging, middle-drag to pan, scroll to zoom, or double-click a point to zoom straight to it — left-click zooms up to that point, right-click zooms in from it.

Data-quality at a glance

NaNs, infinities, subnormals, and dead channels are flagged directly in the channel list, with a tooltip breakdown on hover.

Channel statistics on hover

Sample count, min/max range, and data-quality flags for every channel, right in the file tree.

Thumbnail previews

Every channel gets a small preview plot in the file tree, so you can see the shape of the data before you even select it.

Interactive legend

Hover a series to highlight its trace, right-click to remove it from the plot, left-click to bring it to the front.

Built for scale

Smooth zoom, pan, and redraw — no noticeable latency at 150 million plotted points.

Zero install

A single self-contained .exe under 1.2 MB. No installer, no dependencies, no companion DLLs.

Screenshots*

Twenty channels of synthetic automotive field-test data, stacked by engineering unit
Stacked-by-unit layout — one row per engineering unit, each with its own scale.
File tree showing red NaN, infinity, and subnormal indicators on channel thumbnails
Data-quality indicators — NaNs, infinities, and subnormal values flagged directly on each channel.
Wheel displacement and engine speed channels automatically split across a dual Y-axis
Automatic dual Y-axis — wildly different scales, one readable plot.

* Synthetic data

About

A note on the spirit of this release

EnginPlot is offered as a gift. It’s shared freely because sharing is worthwhile in itself, not because anything is owed in return. There’s no expectation of support, no promise of bug fixes, no roadmap of feature additions, and no obligation to respond to issues or requests. If it’s useful to you, wonderful. If it’s not, set it down and no harm done.

Please arrive with no expectations of the author beyond the software as it sits here today.

This sentiment is offered in the spirit of David Heinemeier Hansson’s writing on open source as a gift freely given. The words here are my own; the spirit is his.

Download

EnginPlot is free and runs on Windows 10+. Version 0.27, 1.1 MB, no installer.

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Nothing to open yet? Download example data (.zip, 650 KB) — all synthetic, generated for testing. Or generate your own with the sample-data scripts.