I have an idea for a script than could generate refracted rays. It would be useful for generating lens schematic.



Idea is that it would work like Extend function, but creating new line segment as follows:
• Select line to refract
• Select transition line or surface
• Type transition refraction index (eg. air to glass 1/1.52)
Result would be a new line segment at a refracted angle.

Here's how refraction line is constructed manually, without any trigonometry. Just scaling perpendicular to normal, then mirroring.

Following, the script could work as follows:

1. Extend refraction line to transition surface-or-line
2. If extended successfully, proceed
3. Get normal from transition surface-or-line
4. Create new line to refract
5. Scale sine of that line to the normal by refraction transition index (typed).
6. Mirror that line along transition surface and normal

I don't know how to write scripts for MoI, so someone maybe wants to do it.

I believe that James can do that with Elephant without not so difficulties! ;)

Hi Fubax, the node editor might be an easier place to start if you haven't done any script programming before at all:
https://moi3d.com/wiki/nodeeditor

- Michael

Hello, I can try the nodeeditor, thank you for suggesting that.

This is the equation I came up with for producing refracted line



And here's the GLSL code that could do just that, I need to look into MoI scripting.

vec3 refract(float n_trans, vec3 incident, vec3 normal)
{
	// Scale normal (assuming normal is an unit vector)
	normal *= dot(incident, normal);
	// Preserve incident vector length as squared value
	float sq_length = dot(incident, incident);
	// Scale incident vector tangentially to normal,
	// by transition refraction index (eg. air/glass=1/1.52)
	incident = n_trans*(incident-normal)+normal;
	// Normalize length of refracted incident, to scale along sine
	return -incident*rsqrt(dot(incident, incident)/sq_length);
}

Maybe someone could implement that.

It would be useful also if the node respected law of reflection. It means to have point/flat light source (solid) with rays (curves) as an input and curved surface - reflector (rotate conic curve) with Rho as a variable. Rays impacted of surface would be reflected to the detector (plane) in specific distance. This would be very nice educative tool. 2D would be enough :-)

Mik