To display force vectors on 1D elements with Optistruct results, you should:

• Load your model and result file at the same time in HyperView
• Select "Advanced" for Result-Math template.
  

To display force vectors on 1D elements with a Nastran SOL106, you should :

• Load your model and result file at the same time in HyperView
• Open the Result Browser
• Click on the name of the model
• Check Small Deformation (This will allow the result template advance to use the undeformed element system to display the vector plot.)
  
• Apply the vector plot (1D elements forces)