Thanks for the explaination. Firstly, I am sorry for improperly presenting what I require. The car's post was just an example. What I actually need is to render vector plot (quiver plot). The car has nothing to do with the arrows. I am working on a scientific application where I need to display vectors over a mesh. Like this one here. The concept of arrows what you interpreted is right. Regardless of what amount user zoom's in/out, the size of arrows should appear same for the user.
Let me explain why I need to scale the arrow size. Suppose the mesh is a huge mesh and the mesh nodes are very densely placed (i.e. very close to each other node). In this case I would get vector plot also dense. i.e. a black patch would appear at that region. So as a user, I would like to zoom that area and see what exactly is happening in that area. Now when I zoom, if I do not scale arrows, they will appear as a patch only. If I scale those arrows, then user will get clear idea what is going on. That's the main Idea behind it.
Anyways, I shall try what you told and get back to you. If you have any further clarification of suggestions, kindly post it here.
Thanks & Regards
Last edited by rakeshthp; 10-02-2013 at 07:56 PM.