RT(nged)

RT(nged) — BRL-CAD MGED Commands 💅

okay so bestie, this is the MGED command page for rt: the one that runs the BRL-CAD rt program with the default options of -s512 -M. The vibe is very “raytrace it and slay,” and all the actual deets are below. 🫶

🌸 NAME 🌸

rt — executes the BRL-CAD rt program with the default options of -s512 -M.

✨ SYNOPSIS ✨

rt [options] [-- objects]

💖 DESCRIPTION 💖

Okay so picture this: rt executes the BRL-CAD rt program with the default options of -s512 -M. Literally those defaults. No cap. 💅

If perspective is turned on, then the -p option will be included with the value of the perspective angle. The current database name is added to the end of the rt command line along with either the specified objects or, if none is specified, the list of currently displayed objects.

The rt program is written such that options may be repeated, and the last occurrence of an option will override any earlier occurrences. That’s the little loophole that lets you specify other size (-s) options. Iconic behavior, honestly. ✨

The rrt command performs a similar function, but may be used to execute other programs as well. The -M option tells rt to read the viewing parameters from standard input. See the man1 page on rt for details.

A related command is saveview, which can be used to create a shell script (batch job) to raytrace this view in the background. Very “set it and forget it” of it. 🦋

🎀 EXAMPLES 🎀

Example 1. Run the rt program to produce a color-shaded image of the current view in MGED.

mged>rt -s1024 -F/dev/Xl

Runs the rt program to produce a color-shaded image of the current view in the MGED display. The image will be 1024 pixels square and will be displayed on a lingering X framebuffer. Slay. 💖

Example 2. Run the rt program to produce a color-shaded image of an object using MGED's current viewing parameters.

mged>rt -C 234/245/255 — roof

Runs the rt program to produce a color-shaded image of the object roof using MGED's current viewing parameters. The image will have a sky-blue background and will be displayed on the framebuffer specified by the FB_FILE shell variable. 🎨

Example 3. Run rt to produce a color-shaded image with increased ambient lighting and ambient occlusion enabled.

mged>rt -A1.2 -c "set ambSamples=64"

Runs the rt program to produce an ambient occlusion color-shaded image of the currently displayed object(s) using MGED's current viewing parameters. Image brightness is increased with the -A ambient 1.2 value (default is typically 0.8). Brightness in dark shadowed sections of the model are then attenuated with the ambient occlusion ambSamples setting which specifies the number of sample rays to shoot. Obsessed with the drama of a good shadow tbh. 🌸

Example 4. Run rt to visualize per-pixel render timing for the current view.

mged>rt -l8 -o current_view_heat.png

Runs the rt program in heat-graph mode. Each pixel is shaded by the high-resolution current-thread CPU time needed by the rendering worker to render that fully shaded pixel, with brighter grayscale pixels indicating pixels that took longer to complete. If a current-thread CPU timer is not available, rt falls back to wall-clock timing. The timing includes shader work such as light visibility and shadow rays, and the grayscale image is normalized for comparative display. The image is written to current_view_heat.png using MGED's current viewing parameters. Heat-map realness. 🔥

👑 AUTHOR 👑

BRL-CAD Team

📬 BUG REPORTS 📬

Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org.

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okay bye bestie 🫶 — source/version: BRL-CAD · manual: RT(nged) · date: not shown in the footer. 💅