Method union

paper-api/src/main/java/org/bukkit/util/BoundingBox.java:579–591

Expands this bounding box to contain (or border) the specified position. @param posX the x position value @param posY the y position value @param posZ the z position value @return this bounding box (now expanded) @see #contains(double, double, double)

(double posX, double posY, double posZ)

     * @see #contains(double, double, double)
     */
    @NotNull
    public BoundingBox union(double posX, double posY, double posZ) {
        double newMinX = Math.min(this.minX, posX);
        double newMinY = Math.min(this.minY, posY);
        double newMinZ = Math.min(this.minZ, posZ);
        double newMaxX = Math.max(this.maxX, posX);
        double newMaxY = Math.max(this.maxY, posY);
        double newMaxZ = Math.max(this.maxZ, posZ);
        if (newMinX == this.minX && newMinY == this.minY && newMinZ == this.minZ && newMaxX == this.maxX && newMaxY == this.maxY && newMaxZ == this.maxZ) {
            return this;
        }
        return this.resize(newMinX, newMinY, newMinZ, newMaxX, newMaxY, newMaxZ);
    }

    /**
     * Expands this bounding box to contain (or border) the specified position.