That's one heck of a commit you've got there...

I may have got a bit behind with version control. A lot behind, in fact. Maybe I'll go back and split this sometime - then again, I probably won't. But hey, at least it's here!

src/main/java/electroblob/wizardry/entity/ICustomHitbox.java

@@ -0,0 +1,31 @@
+package electroblob.wizardry.entity;
+
+import net.minecraft.util.math.Vec3d;
+
+/** This interface allows implementing entity classes to define their own hitbox for wizardry's raytracing and
+ * particle collision methods. Typically, entities implementing this interface will return null from the collision
+ * bounding box methods in {@code Entity} (there are two for some reason) <b>but</b> return true from
+ * {@link net.minecraft.entity.Entity#canBeCollidedWith()} */
+public interface ICustomHitbox {
+
+	/**
+	 * Calculates the point at which the line starting at the given origin and ending at the given endpoint hits this
+	 * entity, if any. Used in raytracing to allow entities to define fully custom behaviour. See
+	 * {@link electroblob.wizardry.entity.construct.EntityForcefield} for an example implementation of a spherical hitbox.
+	 * @param origin The origin of the line.
+	 * @param endpoint The endpoint of the line.
+	 * @param fuzziness Maximum distance around the line that should still count as a hit.
+	 * @return A {@link Vec3d} representing the point hit, or null if there is no intercept. This should be the first
+	 * point that the line hits, i.e. if there is more than one intercept this method should return the one nearest to
+	 * the given origin.
+	 */
+	Vec3d calculateIntercept(Vec3d origin, Vec3d endpoint, float fuzziness);
+
+	/**
+	 * Returns whether the given point is inside this entity.
+	 * @param point The coordinates to test.
+	 * @return True if the point is inside this entity, false if not.
+	 */
+	boolean contains(Vec3d point);
+
+}