How to prepopulate fields while creating a child object from two master detail objects in Salesforce?

Question

I have a custom child object called Order_Assignment__c that has two master detail lookup fields:

1. Order__c
2. Contact

While on the Order__c page I will create a new related Order_Assignment__c record by clicking on the related objects default "new" button to pull up the screen to create a new Order_Assignment__c record (see attached image). Once the screen pops up, it automatically fills out the related Order__c and then I have to manually select the Contact that I would like to relate to the Order_Assignment__c record. Once the two master detail fields have been selected, my goal is to automatically populate multiple fields on the Order_Assignment__c page with values directly from the two master detail objects. Once the values have been populated from the master detail records, the values need to be able to be overridable by the user.

Any guidance on the best way to accomplish this would be greatly appreciated.

Answer 1

If you are okay with populating the other fields based the Order__c and Contact__c fields AFTER saving the record, process builder should work. You can traverse the parent relationship and use those values on your new Order_Assignment_Record__C. If changes are needed, the record can then be edited.

If you have to populate the other fields based the Order__c and Contact__c fields BEFORE saving the record, it is going to be a lot trickier and there is not an out of the box solution.