Hi, I have written a small library using cl-opengl to do skeletal animation which works great. I use vertex arrays in the process. As outlined in opengl-array.lisp under examples, I have a gl array of vertices. To the vertex object in the gl array I added texture coordinates: (gl:tex-coord :type float :components (u v)) In my code, (just like enable vertex and color array); I enable tex coord array ; all texture loading code and creating gl vertices/indices code (gl:enable-client-state :texture-coord-array) ....... (gl:bind-gl-vertex-array gl-vertices) (gl:draw-elements :triangles gl-indices) ........ (gl:enable-client-state :texture-coord-array) However it leads to a memory segment address error. If I go the primitive route, rendering the triangle vertices and texture coordinates, things work fine. Obviously, as for texture coordinates with draw elements; I am missing something. I tried looking up into the source/examples but could not find. [PS: i am no C expert, so am stuck here] Any help appreciated, Let me know in case of any questions, Thanks and Regards, Deepak -- To see a miracle, be the miracle.