Hello,
Situation test carry 20% weightage in the final calculation. Once candidate clears the wriiten test which is round 1 then he/she is guided towards situation test which is round 2 for B.des aspiring students. So, the test is important in final selection and securing the admission. 

As Situation test is basically a hands-on test which is used to evaluate candidate’s skills for material handling and innovative ability. This is done based on the given situation and set of materials. One should keep in mind that no additional material will be provided or allowed. The model will be evaluated on space visualization, innovative and creative use of the given material, the composition of elements, colour scheme, construction skill, the finesse of the model and at last overall presentation. These parameters will then be checked with the write up explaining the concept used in the model constructed. Since the medium of instruction in NIFT Exam is English, the write-up will be in English only. No marks will be given for write-up in any other language.

As there is time in exam you can look previous papers of it. It would be of great help to you in formulating strategy for the paper.

I hope this helps you.
All the best !!