Hi Ken, I still haven't figured this out. Could you give me some more detailed explanations? -- View this message in context: http://vtk.1045678.n5.nabble.com/Error-setting-vertexMC-in-shader-VAO-and-EGL-BAD-DISPLAY-tp5735057p5735143.html Sent from the VTK - Users mailing list archive at Nabble.com.