i used the following code to draw 1/4 of cylinder surface but it doesn't seem accurate. Anyone can point out the problem? Also as it is a meshed surface, how do i fill it? (d is radius of cylinder) GLint nNumPoints=3; GLfloat ctrlPoints[3][3][3]={{{-d,0.0f,1.0f}, {-0.7071f*d,-0.7071f*d,1.0f},{0.0f,-d,1.0f}}, //v=0 {{-d,0.0f,0.0f},{-0.7071f*d,-0.7071f*d,0.0f}, {0.0f,-d,0.0f}}, //v=1 {{-d,0.0f,-1.0f},{-0.7071f*d,-0.7071f*d,-1.0f}, {0.0f,-d,-1.0f}}};//v=2 // the setup function glMap2f(GL_MAP2_VERTEX_3, // Type of data generated 0.0f, // Lower u range 10.0f, // Upper u range 3, // Distance between points in the data 3, // Dimension in u direction (order) 0.0f, // Lower v range 10.0f, // Upper v range 9, // Distance between points in the data 3, // Dimension in v direction (order) &ctrlPoints[0][0][0]); // array of control points // Enable the evaluator glEnable(GL_MAP2_VERTEX_3); // Map a grid of 100 points from 0 to 100 glMapGrid2f(10,0.0f,10.0f,10,0.0f,10.0f); // Evaluate the grid, using lines glEvalMesh2(GL_LINE,0,10,0,10); glEnable(GL_AUTO_NORMAL); [edited by - coda_x on January 13, 2004 4:25:30 AM]