I have this new requirement for an application UI design. There is one instance of the app wherein the user needs to input a lot of info, the recommended wireframe was to put a 3 level tab design (image reference added below), I wanted to know whether there is another UI pattern which I can use to achieve this functionality.
Almost anything else. Filling in that quantity of data manually is very time consuming, very error prone, and very depressing to have to do. If your users have a choice, then they will go elsewhere. If they do not, they will hate you.
I would suggest that firstly, you need to be very harsh about whether you actually need every one - remove any from this form that are optional, and allow the user to add them at another time.
If the data entry is a process, the idea of providing navigation for a linier form process is a little odd. Better make a stepped process users can next/prev through or jump to a specific point along the line. Allowing user to navigate to any part of a form at any time through levels of heirachy removes the linier nature and in tern how far through the process they are. Better keep it linier and allow a 'jump to' contents tool. With a form of this scale some kind of percentage complete indicator, or a decreasing 'todo list' indicator fo some kind.
Better still, as others have suggested, (if possible) make the data capture much simpler - reduce the required fields to a point where completion wouldn't take someone an entire day and require such a complex complex UI.
If you need to collect so much information you really should ask for different pieces of relative information over a workflow of different screens. To require so much information upfront will only upset your users.
Also to validate your users input on both server side and client side would be a nightmare to develop.