Difference between Objects and Parts?  

RE: Difference between Objects and Parts?

Perhaps this give you an answer

https://help.prusa3d.com/en/article/split-to-objects-parts_1751

RE: Difference between Objects and Parts?

Ok heres a basic run down.

Objects - Each Object is the root of a branch in the right hand window area.   Each object is sliced and processed individually.  So overlap an object with another and bad things happen.  An object also must follow several basic rules.  Like all objects must be placed on the print bed.  SO trying to lift an object above the print bed is not allowed, it will just drop to the bed.  As long as some part of the object is on the bed (or raft if enabled) then its ok.
An object can be made up of many parts though.  Parts appear as branches of the main object in the right hand tree (so like sub folder in explorer).  You can select parts by clicking on them in the tree view.  Parts can be moved around and floated above the bed unlike objects.  As long as some part of the parent object is touching it doesnt matter.  Also overlapping PARTS are sliced properly and clip each other.

Splitting to Objects basically is destructive, in that all the individual pieces will all fall to the bed.  As they are now a bunch of disassociated models.  Unless there is some over riding reason to split to objects then its best not to.

Remember that you can only select a part by using the tree view and not on the plater view.  If you try and grab it there it will just grab the whole parent object.  

RE: Difference between Objects and Parts?

That makes a lot of sense.

So, if I were to download pre-oriented files for the mk3s and wanted to print them on a mini, it would be better to chose the "destructive" method, by splitting into objects, so that the slicer takes care of things like spacing automatically?

RE:

Not really no in most cases.  As the only real reason for an object to be made up of parts is at design time and you generally find that they need to be in their relative locations.  

For example if someone designed a truck model in cad.  When imported into PS then it would come is as say 'Truck' .  Its one object.  If you split to parts the tree list might expand into say 50 parts.  Like eacg wheel rim would be one object, each whell hub might be another.  The steering wheel might be separate.  The truck chassis.  The load bed etc etc.  If the designer made the truck out of 50 modelled objects then each would be a part.  When split to parts they still retain all their relative positioning.  Although as parts you could say delete just the steering wheel or the bed.  That way you would be able to print the truck without the bed.

If you split to objects then you suddenly have all 50 parts falling to the bed as if you had imported 50 models.  You would then have to arrange them all, place to face etc.  The individual objects might not also be suitable to be printed and glued together.  The may have modelled the wheel hub without an axel hole so it might not fit on the chassis axel for example.
It really depends on the object/model you are printing.

Best thing is to experiment and load different models and try the split to parts/objects and see what you get.  It will be the best way to learn.  You also rapidly get to see just how poorly some models are constructed 😉

If you have an example you are working with then post the zipped up project file so we can possibly show with examples.

RE: Difference between Objects and Parts?

EXCELLENT explanation THANK YOU.

as a self-appointed 'dummy', I annotated your explanation a bit.  I hope it helps others as it helped me.

Difference between Objects and Parts?

Ok here’s a basic run down.

Each OBJECT is the root of a branch in the right hand window pane.   

Within each OBJECT can be multiple Parts.

OBJECTs are the Assembly, and Parts are the components

Parts appear as branches of its parent OBJECT in the right hand pane

(This is like folders in Explorer; but unlike Explorer there are only these 2 levels in the Slicer). 

Each OBJECT is sliced and processed individually. 

+Do not attempt to overlap  OBJECTs, or bad things happen.  

+ OBJECTs must be placed on the print bed. 

   So trying to lift an OBJECT above the print bed is not allowed, it will just drop to the bed. 

   But as long as some piece of the OBJECT is on the bed (or raft if enabled) then its ok.

You can select Parts only by clicking on them in the tree view, not the Plater view. 

   If you try and grab it in the Plater view, it will just grab the whole parent OBJECT. 

Unlike OBJECTs,  Parts can be moved around and can be floated above the bed. 

(think of it as if the ‘Part’ is resting on the ‘OBJECT, and the OBJECT is resting on the print bed)

Also overlapping Parts are sliced properly and clip each other.

SPLITTING:

Splitting into OBJECT basically is destructive: It turns all pieces into root-level OBJECTs,

(like if you had the number ‘8’ as a cutout, it would create each circle in the ‘8’ as a new OBJECT.)

And as an OBJECT, all the individual pieces will all fall to the bed, since they are now a bunch of disassociated models. 

Unless there is some overriding reason to split to objects then it’s best not to.