AFX for Creo 3.0 Student Version

Hello forum,

I came to this forum because I find difficulties in creating a metal cart. Indeed, I drew the frame with sketches that have a 3D shape with curves so when I position the tube on straight lines it does it on the other hand for curves (rounding) it only creates on one plane the others no!
If someone can help me I can attach the file 
Thank you in advance for your help