I just started getting involved in web visualizations, so I'm totally novice. My goal is to display a family tree where a root node would have both multiple parents and children. While looking for a solution I found this example: http://bl.ocks.org/jdarling/2503502
It's great because it seems to have the feature I need. However, I would like to alter the orientation (top-to-bottom). I tried to do so using this example: http://bl.ocks.org/mbostock/3184089 but failed.

My code:

var tree = d3.layout.tree()

    .size([height, width]);



var diagonal = d3.svg.diagonal()

    .projection(function(d) {

        return [d.x, d.y];

    });



var elbow = function (d, i){

    var source = calcTop(d.source);

    var target = calcTop(d.target);

    var hx = (target.x-source.x)/2;

    if(d.isRight)

        hx = -hx;

    return  M + source.x + , + source.y

          + H + (source.x+hx)

          + V + target.y + H + target.x;

};



var connector = elbow;



var calcTop = function(d){

    var top = d.x;

    if(!d.isRight){

        top = d.x-halfHeight;

        top = halfHeight - top;

    }

    return {x : top, y : d.y};

};



var vis = d3.select(#chart)

    .append(svg)

    .attr(height, height + margin.top + margin.bottom)

    .attr(width, width + margin.right + margin.left)

    .append(g)

    .attr(transform, translate( + margin.left + , + margin.top + ));



d3.json(tree.json, function(json) {

    root = json;

    root.x0 = height / 2;

    root.y0 = width / 2;

    var t1 = d3.layout.tree()

        .size([halfHeight, width])

        .children(function(d){

            return d.winners;

        });

    var t2 = d3.layout.tree()

        .size([halfHeight, width])

        .children(function(d){

            return d.challengers;

        });

    t1.nodes(root);

    t2.nodes(root);



    var rebuildChildren = function(node){

        node.children = getChildren(node);

        if(node.children)

            node.children.forEach(rebuildChildren);

    }

    rebuildChildren(root);

    root.isRight = false;

    update(root);

});



var toArray = function(item, arr){

    arr = arr || [];

    var i = 0, l = item.children?item.children.length:0;

    arr.push(item);

    for(; i < l; i++){

        toArray(item.children[i], arr);

    }

    return arr;

};



function update(source) {

// Compute the new tree layout.

var nodes = toArray(source);



// Normalize for fixed-depth.

nodes.forEach(function(d) { d.x = d.depth * 180 + halfHeight; });



// Update the nodes…

var node = vis.selectAll(g.node)

    .data(nodes, function(d) { return d.id || (d.id = ++i); });



// Enter any new nodes at the parent's previous position.

var nodeEnter = node.enter().append(g)

    .attr(class, node)

    .attr(transform, function(d) {

        return translate( + source.x0 + , + source.y0 + );

    })

    .on(click, click);



nodeEnter.append(circle)

    .attr(r, 1e-6)

    .style(fill, function(d) {

        return d._children ? lightsteelblue : #fff;

    });



nodeEnter.append(text)

    .attr(dy, function(d) { return d.isRight?14:-8;})

    .attr(text-anchor, middle)

    .text(function(d) { return d.name; })

    .style(fill-opacity, 1e-6);



// Transition nodes to their new position.

var nodeUpdate = node.transition()

    .duration(duration)

    .attr(transform, function(d) {

        p = calcTop(d);

        return translate( + p.x + , + p.y + );

});



nodeUpdate.select(circle)

    .attr(r, 4.5)

    .style(fill, function(d) {

        return d._children ? lightsteelblue : #fff;

    });



nodeUpdate.select(text)

    .style(fill-opacity, 1);



// Transition exiting nodes to the parent's new position.

var nodeExit = node.exit().transition()

    .duration(duration)

    .attr(transform, function(d) {

         p = calcTop(d.parent||source);

         return translate( + p.x + , + p.y + );

    })

    .remove();



nodeExit.select(circle)

    .attr(r, 1e-6);



nodeExit.select(text)

    .style(fill-opacity, 1e-6);



// Update the links...

var link = vis.selectAll(path.link)

    .data(tree.links(nodes), function(d) { return d.target.id; });



// Enter any new links at the parent's previous position.

link.enter().insert(path, g)

    .attr(class, link)

    .attr(d, function(d) {

        var o = {x: source.x0, y: source.y0};

        return connector({source: o, target: o});

    });



// Transition links to their new position.

link.transition()

    .duration(duration)

    .attr(d, connector);



// Transition exiting nodes to the parent's new position.

link.exit()

    .transition()

    .duration(duration)

    .attr(d, function(d) {

        var o = calcTop(d.source||source);

        if(d.source.isRight)

            o.x -= halfHeight - (d.target.x - d.source.x);

        else

            o.x += halfHeight - (d.target.x - d.source.x);

        return connector({source: o, target: o});

    })

    .remove();



// Stash the old positions for transition.

nodes.forEach(function(d) {

    var p = calcTop(d);

    d.x0 = p.x;

    d.y0 = p.y;

});



// Toggle children on click.

function click(d) {

    if (d.children) {

        d._children = d.children;

        d.children = null;

    } else {

        d.children = d._children;

        d._children = null;

    }

update(source);

}
}

Would really appreciate the help!