renderPoint = function(d, i) {
const sel = d3.select(this);
d.l1 = sel
.append("path")
.attr("stroke", girderColor)
.call(l(unity));
d.pt1 = sel
.append("circle")
.attr("fill", girderColor)
.attr("r", ptR)
.call(pt(unity));
d.l1AB = sel
.append("path")
.attr("stroke", girderColor)
.attr("d", line([d.A, d.B]));
d.lAB = sel
.append("path")
.attr("stroke", girderColor)
.call(l(d.A));
d.ptAB = sel
.append("circle")
.attr("fill", girderColor)
.attr("r", ptR)
.call(pt(d.A));
d.lA = sel
.append("path")
.attr("stroke", color(null, 0))
.call(l(d.A));
d.lB = sel
.append("path")
.attr("stroke", color(null, 1))
.call(l(d.B));
d.ptA = sel
.append("circle")
.attr("fill", color(null, 0))
.attr("r", ptR)
.call(pt(d.A));
d.ptB = sel
.append("circle")
.attr("fill", color(null, 1))
.attr("r", ptR)
.call(pt(d.B));
}