Enabling Z-Buffer in Creo API

I am developing plugin for Creo 3.0 and we have problem with Z-Buffer. What we want is to draw lines and have Z-Buffer enabled. I don´t know how to achieve this point. I am using: wSession->DrawPolyline(pnts); to draw points. Could anyone tell me how to enable z-buffer in Creo API? Thanks in advance, Grzegorz

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