Multiple bodies in one part end up all in the center. Never a problem before 2.4 update.  

RE: Multiple bodies in one part end up all in the center. Never a problem before 2.4 update.

I need to add that I am saving it as a 3MF and everything it ending up in the middle.  I went back to Fusion 360 and saved it at STL and they are all in one place.  Now my question is how to do this with 3MF.  STL is no problem.

RE: Multiple bodies in one part end up all in the center. Never a problem before 2.4 update.

Read the release notes for 2.4.  All of them from the first alpha onwards.

It was changed because it was requested to make bodies in a 3mf behave the same way as stl files.

stl files by there very nature dont really have a concept of origin as related to an outside space.  As such when you load in an stl PS places it in the centre of the build plate.  An single stl made of of multiple parts have relationship to each other so when imported the 'group' of parts gets placed in the centre.

Now a 3mf file is used as a PS project format.  The same format is also used by Fusion (and others) as a file type for output too.  The thing about 3mf though as a format is it can define many things inside it.  So the vector information for the models.  Their relationship in space to each other.  Their position relative to an exterior world space, the materials they are made from, colour, texture etc etc.  Its up to the software creating the 3mf what types of data it stores in there and how it uses that data.  So a Prusa Slicer 3mf will store different data (what it needs to store) in there compared to a fusion 360 3mf.

What was happening was all the relative positioning from the users F360 workspace was also being used.  So if during your design phase you had a part located a metre off to one side then when loaded the part was still a metre off to the side, so outside the print bed.  Combine that with the restriction in PS of not allowing Objects to be placed in  mid air off the bed and some parts would keep their xy coordinates and then lose their Z as they get dropped to the same height as the bed.  Personally I thought that behavior was correct, have it somewhere in your project then why shouldnt it be the same when loaded into PS.

However, it was causing all sorts of confusion, even though it was loading in exactly as the user had it in their workspace.  SO after several quite long threads over on github the functionality was changed to make loading in of 3mf parts works in a similar way to stl files.  All separate bodies in a F360 project work like separate stls and all get placed in the middle now. 

There were also changes around the name of bodies used etc too.