Curve for node block

image
i want this much curve in my nodes block i used rectanglerounded and parameter1.
image
this is my node here i gave parameter1: 40

Try this figure:

go.Shape.defineFigureGenerator("CapsuleH", function(shape, w, h) {
  var geo = new go.Geometry();
  if (w < h) {
    var fig = new go.PathFigure(w/2, 0, true);
    fig.add(new go.PathSegment(go.PathSegment.Bezier, w/2, h, w, 0, w, h));
    fig.add(new go.PathSegment(go.PathSegment.Bezier, w/2, 0, 0, h, 0, 0));
    geo.add(fig);
    return geo;
  } else {
    var fig = new go.PathFigure(h/2, 0, true);
    geo.add(fig);
    // Outline
    fig.add(new go.PathSegment(go.PathSegment.Line, w-h/2, 0));
    fig.add(new go.PathSegment(go.PathSegment.Arc, 270, 180, w-h/2, h/2, h/2, h/2));
    fig.add(new go.PathSegment(go.PathSegment.Line, w-h/2, h));
    fig.add(new go.PathSegment(go.PathSegment.Arc, 90, 180, h/2, h/2, h/2, h/2));
    return geo;
  }
});

example: https://codepen.io/simonsarris/pen/MWxwooX?editors=1010

This will actually be a built-in figure in GoJS 3.0 (to be released next year)

You have given the code for styling whole block but i want to place circle inside my nodeBlock

Main the primary node panel a Spot panel and put a circle inside of it: https://codepen.io/simonsarris/pen/MWxwooX?editors=1010

presumably you want an auto panel that has a circle, and not just a circle, to add text too