RTSCALE(1)

💖 NAME — rtscale(1) 💖

rtscale — plot a measuring scale for an rt/rthide UNIX-Plot image. This is the BRL-CAD RTSCALE(1) manual page, bestie 🫶.

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✨ SYNOPSIS ✨

rtscale _width_ _units_ _intervals_ _file.log_ [_string_] > scale.plot3

🎀 DESCRIPTION 🎀

Okay so rtscale generates a UNIX-Plot (peep plot3(5)) of a labeled measuring scale. This thing is made to be overlaid onto a raytraced image so you can measure geometry accurately — measurement era, periodt 💅.

It is most often paired with rthide(1): rthide produces a hidden-line plot of the geometry, and rtscale produces a matching plot containing only a scale. Concatenating the two files, with the scale first, yields a finished plot complete with a scale. Scale first, always — iykyk 🫶.

rtscale reads the RT log file written by the rt(1)-family run and uses the view, orientation, eye position, and size recorded there to build the view-to-model matrix. The scale is laid out in view coordinates, drawn as a line with tick marks ending on a "nice" rounded value, and placed in the lower left corner of the image. An optional descriptive string is drawn beneath the scale to identify the view or model. Lower-left-corner realness ✨.

The positional arguments are:

• width — length of the scale expressed in units.
• units — unit name passed to bu_units_conversion; any metric or English unit is accepted (for example mm, cm, m, in, ft). Metric girlies and English-unit besties are both welcome 🫶.
• intervals — number of tick-mark intervals along the scale.
• file.log — RT log file from which the view2model matrix is computed.
• string — optional descriptive label drawn under the scale.

🌸 EXAMPLES 🌸

Example 1. Scale a hidden-line rendering and view it

rthide -o model.plot3 model.g component 2> rt.log
rtscale 30 mm 10 rt.log "UH-60 a90 e0" > scale.plot3
cat scale.plot3 model.plot3 > model.w.scale.plot3
plot3rot -a35 -e25 -g model.w.scale.plot3 | plot3-fb

rthide renders the geometry and records the view in rt.log. Then rtscale does its little scale moment and emits a 30 mm scale with ten intervals and a descriptive label. The scale must be concatenated ahead of the model plot so it survives rotation; plot3rot(1) reorients the combined plot and plot3-fb(1) displays it on a framebuffer. Descriptive strings longer than 28 characters are truncated by plot3-fb(1). 28 characters max, bestie — don't test her 😭.

👀 SEE ALSO 👀

brlcad(1), mged(1), plot3rot(1), plot3-fb(1), rt(1), rthide(1), librt(3), libbv(3), plot3(5), ray(5V)

💀 DIAGNOSTICS 💀

Numerous error conditions are possible, usually due to errors in the geometry database or RT log file. Descriptive messages are printed on standard error. Usually it's the geometry database or RT log acting up 🫠.

👑 AUTHOR 👑

BRL-CAD Team

📜 COPYRIGHT 📜

This software is Copyright (c) 1991-2026 by the United States Government as represented by U.S. Army Research Laboratory.

🐛 BUG REPORTS 🐛

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org. No carrier pigeon, just email 💌.

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Cute sign-off: BRL-CAD RTSCALE(1) — footer source/version and manual name only, no explicit date printed here, so I'm not inventing one 🫶💜.