If you have ever wanted to check for Interference in between multiple weldment structural members in a SolidWorks Part, you will discover that there is no interference detection tools available while working on a part.  Any attempt to add the interference detection icon to your toolbar results in a greyed out button*(unavailable).  Now what?  Well with this tip, you will discover that you have 2 options for checking for interference on a weldment part:

1) Simply create an assembly with your weldment part *(no other parts are needed) and run Interference Detection from the pull-down Tools/Interference Detection or from the Evaluate tab on the CommandManager.  Make sure to use the following option, ‘Include Multi-body part interferences’.

2) In the weldment part file you can use the Combine Feature to check between 2 structural members. From the pull-down Insert/Features/Combine, simply select the ‘Common’ option and select 2 structural members to check if there is any overlapping volume between them.  You can use the Preview button in the command and you will see if there is any interference.  If there are none, you will get the following message: “Unable to create single body common to the input bodies” which would mean that there is no interference.