Seeking Real-World Experiences with Bi-Directional Filtering in Power BI

Hello HamidBee 

1. 2. 

use cases of bi-directional  : is when you want the slicers in a report to filter each other ( since they dont because slicers comes from dimensions ) . but you should avoid bi-directional for this purpose and use a measure in the filter pane :  filter on visual to achieve filtering between each others. 

bi-directional could be useful  if you are working with snowflake schema ( which is not recommended for bi tools .  the recommended model is always a star schema ) 

let us say, that you have  the following tables : 

factsales ,  product, sub-category , category

this is a snowflake schema, where

cateogry is linked to sub-cateogry,

sub-category is linked to product and

product is linked to factsales.

the filter in this schema propagate from

cateogry -- >  sub-category 

sub-cateogry -- >  product

product -->  factsales

so maybe the requirement is that to add 2 slicers on a page, subcategory name and categoryname,

and that they both filters each other.

base on the relationship above,   category slicer will filter subcategory due that the filter propagates from the 1 to the many relationship.

but subcategory slicer will never filter category unless you create w bi-directional filter in the model, or using a dax measure that will propagates the filter from category to sub category ,

( NB : in the example above, product, sub-category and category should be merged into one table , but you never know what you ran into in the real world . since not every model you will face will be perfect ) .

3. 

if you have many bi-directional in your model , you will have so much trouble understanding your dax, especially when writing complex dax. 

i ran into a model with alot of bidirectionals,  it was a nightmare to understand how the filters were applying in the model . and i was creating a complex dax.  so i was obliged to disable relationships and enable relationships in my dax measure to get to the correct data. 

my thought whenver you face a problem when you think that bi-directional will solve your problem. STOP !  think about how to restructure your model to avoid using  it .

if not possible,  try going to dax .

hope this clarify some of the things you asked . 

best regards .