I noticed that you already asked this question in our support ticketing system and you can find my answer there. However, I will post my reply also here to contribute to our community.
"Note that our RadChartView suit doesn't support 3D visualization. Such kind of visualization does not help the end user to better understand the provided data. This is why 3D feature has not been implemented yet and its implementation priority is low.
On the other hand, we have already logged Funnel 2D series feature request in our feedback portal and we are monitoring our customers' demand for such series. If you are interested in this type of visualization you can track the item's development status by following it. Keep in mind that if the item collects enough votes we will reconsider its implementation."
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