Hy, I would like to calculate the curl of the speed... the problem is that i don't know how to do it exactly: My method is: I open my post file _>select uvw velocity then clik on GET data ->after I go to POST->GET USER DATA->choose in data type :VERTEX after I clik apply Then I go to operate choose curl and whem I accept He tells me error you have to load a vector field So I do not understand how to proceed Please help me thanks

You have to download velocity components with the smooth option on so you get vertex values. Then go to "list/prostar registers" and use the curl command as you did. you can check in the output window to check if it has been done GET USER DATA is for other files (written by the user) and not the post file. good luck !

Thanks a lot It worked... And just another question: When you want to calculate the gradient of the uvw component what does the computer doe because normaly I should have 9 components for each point no? and he just give me 3 components???? thanks for your help