OpticalBench, Lens and Ray

OpticalBench is manim-physics’ Lens and Ray: lenses on one horizontal axis, and rays traced through them from left to right. Lens::thin(x, focal) is a thin lens, Lens::thick(x, r1, r2, index, thickness) a real one from its radii, refractive index and thickness (focal_length() is the lensmaker’s equation). Radii are positive when the centre of curvature is to the right, so a biconvex lens has r1 > 0 and r2 < 0; a flat side is f64::INFINITY. The rays are traced with paraxial optics, surface by surface, and a ray that meets a lens outside its height stops there. Each lens shows its front and back focal points, F and F', found by tracing a parallel ray, so a thick lens’s sit at its focal distances from its surfaces. Gallery scenes: OpticalBench, Lens.

OpticalBench 3.5 sPlayUnmuteCopy render command

Lens 3.5 sPlayUnmuteCopy render command

Parallel rays focus through a thin lens:

use fframes_kit::prelude::*;

fn bench<'a>(ui: &mut Ui<'a, '_, '_>) -> Svgr<'a> {
    let rays = (0..7)
        .map(|i| Ray::new((-6.0, -0.9 + 0.3 * f64::from(i)), (1.0, 0.0)))
        .collect();
    ui.show(OpticalBench {
        lenses: vec![Lens::thin(0.0, 2.5)],
        rays,
        x_range: (-6.5, 6.5),
        delay: 0.5,
        enter: Some(Create::default().into()),
        ..ui.defaults()
    })
}

For a thick lens followed by a diverging thin lens:

use fframes_kit::prelude::*;

fn bench<'a>(ui: &mut Ui<'a, '_, '_>) -> Svgr<'a> {
    let rays = (0..7)
        .map(|i| Ray::new((-6.8, -0.9 + 0.3 * f64::from(i)), (1.0, 0.0)))
        .collect();
    ui.show(OpticalBench {
        lenses: vec![Lens::thick(-3.0, 2.4, -2.4, 1.5, 0.5), Lens::thin(2.6, -2.0)],
        rays,
        delay: 0.5,
        ..ui.defaults()
    })
}

API

Components are plain structs. Set the fields you need and fill the rest with ..ui.defaults(): the defaults below come from the current theme (theme. values are fields of Theme).

OpticalBench

Manim-physics’ Lens and Ray on one axis: lenses on a horizontal axis at height axis_y from x_range.0 to x_range.1 (units of ui.space), and rays traced through them to x_range.1. With focal_points each lens’s front and back focal points are dots labelled F and F', found by tracing a parallel ray through the lens, so for a thick lens they sit at its focal distances from its surfaces, not from its middle. The rays draw on one after another from delay seconds after the local start (ray_time each, stagger apart). The axis and lenses draw with enter, the rays and labels with parts_enter.

Field	Type	Default	Description
lenses	Vec<Lens>	Vec::new()	The lenses on the axis, each with its position and shape.
rays	Vec<Ray>	Vec::new()	The rays traced through the lenses to the right end of x_range.
axis_y	f64	0.0	Height of the horizontal axis, in units of ui.space.
x_range	(f64, f64)	(-7.0, 7.0)	Left and right ends of the axis in units of ui.space; rays are traced up to the right end.
focal_points	bool	true	Marks each lens’s front and back focal points with a dot.
labels	bool	true	Writes F and F' under the focal points.
delay	f32	0.0	Seconds after the local start before the first ray begins to draw.
ray_time	f32	0.8	Seconds each ray takes to draw.
stagger	f32	0.25	Seconds between the start of one ray and the next.
lens_color	Color	theme.colors.text	Colour of the lenses, the focal points and their labels.
ray_color	Color	theme.colors.highlight	Colour of the rays.
guide_color	Color	theme.colors.muted	Colour of the dashed axis.
stroke_width	f32	theme.stroke.regular	Width of the lens outlines in pixels; rays use the theme’s thin width.
enter	Option<EnterAnim>	None	How the axis and lenses draw in; None shows them from the start.
exit	Option<ExitAnim>	None	How the axis and lenses leave at the end of the container; None stays.
parts_enter	Option<FadeIn>	None	How the rays and labels fade in; None for none.
parts_exit	Option<FadeOut>	None	How the rays and labels fade out before the end; None for none.

Feature physics · Source