create 3d shape in google earth plugin

Question

first of all thanks for reading. I have a web application that heavily uses Google Earth Plugin to show some sensor data and other stuff. I'm trying to give the user the capability to define areas and volumes drawing them in the plugin. I was able to add area features (such as creation, visualization, editing and deletion). Now i'm working on volumes but i really do not know what is the best way to handle them. An inportant thing to note is that i'm only interested in volumes with parallel upper and lower surface (no pyramid, no complex figures, only prisms) The first idea that came in my mind is to create a custom object made of 2 polygon and an array of edges to connect every polygon vertex of the upper surface to the respective one in the lower surface. Something like:

    //Create the upper surface (polygon)  
    var aPolygonUpperPlacemark = ge.createPlacemark("");
    var aPolygonUpper = ge.createPolygon("");
    aPolygonUpper.setAltitudeMode(ge.ALTITUDE_RELATIVE_TO_GROUND);
    aPolygonUpperPlacemark.setGeometry(aPolygonUpper);
    var aOuterUpper = ge.createLinearRing("");
    aPolygonUpper.setOuterBoundary(aOuterUpper);
    ge.getFeatures().appendChild(aPolygonUpperPlacemark);

    //Create the lower surface (polygon)
    var aPolygonLowerPlacemark = ge.createPlacemark("");
    var aPolygonLower = ge.createPolygon("");
    aPolygonLower.setAltitudeMode(ge.ALTITUDE_RELATIVE_TO_GROUND);
    aPolygonLowerPlacemark.setGeometry(aPolygonLower);
    var aOuterLower = ge.createLinearRing("");
    aPolygonLower.setOuterBoundary(aOuterLower);
    ge.getFeatures().appendChild(aPolygonLowerPlacemark);

    var myPrism = {
        upperSurface: aPolygonUpperPlacemark,
        lowerSurface: aPolygonLowerPlacemark,
        edges: new Array()
    };

The proble here is that the lateral surfaces will not get displayed as real surfaces but only as lines. On the other hand i could probably create another polygon for each lateral surface but this would make the management of such a 3d shape more complex than what i'd like it to be.
So my question is, is there any better way to handle 3d shapes or maybe a built-in geometry?
Nota that i cannot rely in 3d models (so external Kmz cannot be loaded) as at the end the 3d shape creation will be a user's feature.

Answer 1

Just create the upper polygon (e.g. ensure the coordinates include altitude), and then ensure is set to 1. You can do this in the API using setExtrude(true).

See https://developers.google.com/kml/documentation/kml_tut#polygons for details

I'd also recommend you check out the utility library - it makes things like this much more concise. See for example this extruded polygon example: http://earth-api-utility-library.googlecode.com/svn/trunk/extensions/examples/poly-draw-extruded.html