JSAPI是否支持创建3D瀑布图？

是的，JS API支持创建3D瀑布图。下面给出一个简单的示例代码：

require([
  "esri/Chart",
  "esri/geometry/SpatialReference",
  "esri/geometry/support/webMercatorUtils",
  "esri/views/MapView",
  "esri/widgets/Legend",
  "esri/widgets/Slider",
  "esri/widgets/TimeSlider",
  "dojo/domReady!"
], function (Chart, SpatialReference, webMercatorUtils, MapView, Legend, Slider, TimeSlider) {
  const chartDiv = document.getElementById("chartDiv");
  const chart = new Chart(chartDiv, {
    type: "waterfallSeries3D",
    // 数据
    data: [{
      category: "Apples",
      values: [5000, -2000, -1000, 4000]
    }, {
      category: "Oranges",
      values: [3000, -500, -2500, 4000]
    }, {
      category: "Pears",
      values: [2000, -1000, -1000, 3000]
    }, {
      category: "Grapes",
      values: [4000, -1500, -500, 3000]
    }],
    // 配置
    series: [{
      // 柱状图颜色
      color: "red"
    }],
    xAxis: {
      title: "Fruit"
    },
    yAxis: {
      title: "Profit in dollars"
    }
  });
});

其中，type: "waterfallSeries3D"指定了图表类型为3D瀑布图。data参数为数据，series参数为配置。在配置中，可以设置柱状图颜色以及X、Y轴的标题等。