I am having some problem using the gluNurbsCurve() function The following code works fine , it draw the curves out but once I add more control points and knots. It wont draw anything. Anyone knows does the gluNurbsCurve function limit to only 4 control points? (I want to draw a curve that has 6 control points. GLfloat ctrlpoints[4][3] = { { -4.0, -4.0, 0.0}, { -2.0, 4.0, 0.0}, {2.0, -4.0, 0.0}, {4.0, 4.0, 0.0}}; GLfloat knots[8] = { 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0 }; GLUnurbsObj* nurbs = gluNewNurbsRenderer(); void display(void) { gluBeginCurve(nurbs); gluNurbsCurve(nurbs, 8, knots, 3, &ctrlpoints[0][0], 4, GL_MAP1_VERTEX_3); gluEndCurve(nurbs); } The following is what I tried to do and wont work: GLfloat ctrlpoints[6][3] = { { 2.4, 0.0, 5.4}, { 1.7, 0.0, 4.8}, {1.6, 0.0, 4.3}, {2.0, 0.0, 4.1}, { 2.7, 0.0, 4.4 }, { 3.3, 0.0, 4.9 }}; GLfloat knots[10] = { 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, 1.0, 1.0, 1.0, 1.0 }; GLUnurbsObj* nurbs = gluNewNurbsRenderer(); void display(void) { gluBeginCurve(nurbs); gluNurbsCurve(nurbs, 10, knots, 3, &ctrlpoints[0][0], 4, GL_MAP1_VERTEX_3); gluEndCurve(nurbs); } Anyone know why?? Thanks

Hi

Thanks for the reply, I manage to get an answer from another forum (OpenGl).
Is to do with the knots, thanks again :)

Cross posted to the OpenGL forum here), I'm closing this one to prevent people getting dragged into it and keeping the other open as it has more replies