1.12 How do I get the location and direction of a model part?

[TheRPGAdventurer]

I am working on a dragon with fire breathing. I wanna make the flames go out in the dragon's mouth but I cannot get the location of a dragon's mouth. Ghasts use their eyeheights as a location for their fireballs origin when firebreathing.

[Lenardjee]

how do you create the dragon model? can I see the code that creates it?

[TheRPGAdventurer]

Just now, Lenardjee said:

how do you create the dragon model? can I see the code that creates it?

DragonModel: https://pastebin.com/Uks47Smx

DragonAnimator: https://pastebin.com/4YyaNJgP

 

[jabelar]

Sorry but you just have to work it out. Based on how your model is built up and animates you'll have to do all the trigonometry involved. It might be easiest to actually draw it out on paper and figure it out. But basically you need to start from the body position and depending on the rotation figure out where the neck attaches, and then based on the neck rotation figure out where the head attaches, and then based on the head rotation figure out where the mouth would be.

[Lenardjee]

Hold on, baking some formulas here, will be done in an hour or so

EDIT:

probably a bit longer

Edited April 10, 2018 by Lenardjee

[Lenardjee]

public class Point3d {

	public double x, y, z;
	
	public Point3d(double x, double y, double z) {
		this.x = x;
		this.y = y;
		this.z = z;
	}
	
	public double distance(Point3d p) {
		return Math.sqrt(Math.pow(p.z - this.z, 2) + Math.pow(Math.sqrt(Math.pow(p.x - this.x, 2) + Math.pow(p.y - this.y, 2)), 2));
	}
	
	/**Rotates the point around the given {@code rotationCentre}
	 * with the given {@code jaw} and {@code pitch}
	 * The vertical rotation ({@code pitch}) will be done after the horizontal rotation ({@code jaw}),
	 * over the x axis that is first rotated over the y axis by {@code pitch} radians.
	 * <p>
	 * @param rotationCentre - what does it say?
	 * @param pitch - the vertical rotation angle
	 * @param jaw - the horizontal rotation angle
	 * @return the Point3d that is calculated to be the position of this point after the rotations
	 * and changes the location of this point to the return value
	 */
	public Point3d rotate(Point3d rotationCentre, double pitch, double jaw) {
		double d = this.distance(rotationCentre);
		Point3d firstRotationPoint = new Point3d(
				rotationCentre.x + (d * Math.cos(jaw)),
				this.y,
				rotationCentre.z + (d * Math.sin(jaw))
				);
		this.x = rotationCentre.x + (firstRotationPoint.x - rotationCentre.x) * Math.cos(pitch);
		this.y = rotationCentre.y + (d * Math.sin(pitch));
		this.z = rotationCentre.z + (firstRotationPoint.z - rotationCentre.z) * Math.cos(pitch);
		return new Point3d(
				rotationCentre.x + (firstRotationPoint.x - rotationCentre.x) * Math.cos(pitch),
				rotationCentre.y + (d * Math.sin(pitch)),
				rotationCentre.z + (firstRotationPoint.z - rotationCentre.z) * Math.cos(pitch)
				);
	}
}

Ok, this is really only useful for calculating the position of 1 of the rotation points, that is, if and only if the dragon hasn't rotated their entire body. I'm working on a formula to make it relative to previous rotations of parent parts, but that might take some time, I'll try my best to get it done.