how i can simulate the free flight mission for tall structures, towers. like a spiral, helical path etc. any tips other than pilot skills.
There is currently no way to do helicoidal flights or in a general way 3 Dimensions flights using pix4Dcapture. Indeed, in the available missions that can be planned, the flight height of the drone will remain the same all along the flights. You can learn more about the different missions available here.
However, depending on the object/structure to be reconstructed, it is possible to make several circular missions at different flight heights and then process your datasets in Pix4Dmapper which would be the equivalent of a 3D flight. Also, the Free Flight mission can be useful.
I suggest you have a look at the following articles on our Knowledge Base:
if I have a 3D Flight Path can I upload it to Pix4D wherein I define where it has to take the shots. In my case say Helical.