Part design object single solid only?

[NormandC]

If a body is split into two distinct shapes by an operation such as my groove, perhaps it would make sense to split these shapes into separate Bodies in the FreeCAD document? There may be great reasons for not doing this, but from the perspective I'm seeing it, that seems to be an accurate representation of what is actually happening.

This point is going to be moot sooner or later, because eventually (maybe sooner than later) multiple bodies will be supported inside a Body. People have complained too much about this restriction for years. ickby (the last PartDesign lead developer) has conceded, as has wmayer. realthunder has already implemented it in his FreeCAD fork. https://github.com/realthunder/FreeCAD_ ... issues/192

People will be happy, but I can't help but see the lack of consistency this will bring. The definition of a body in geometry and in CAD, as I wrote, is a single volume; but the PartDesign "Body" will eventually contain multiple bodies. Go figure.

PartDesign is FreeCAD's "Feature workbench" from what is done inside. Other workbenches have names reflecting the result, such as Part WB, TechDraw, Path, FEM, ... Following that concept, PartDesign is a "Body workbench".

I'm sorry Chris, but that concept is simplistic. AFAIK Path may have been named that way because there was a CAM module predating Path in FreeCAD so the name was taken. Part wb does not actually have a name that reflects the result. According to your scheme, it should be named "Shape workbench".

For anyone new coming to FreeCAD, it does not make sense to name workbenches according to the name chosen for a specific tool in it. It would be far more sensible to name it according to its fundamental purpose. Arch follows that principle, as do FEM and yes, TechDraw, because its ultimate purpose is to produce technical drawings, nothing more, nothing less. What is the ultimate purpose of PartDesign? To make Bodies? Of course not. PartDesign is a high-level workbench with specialized tools for mechanical design. Body is just the name of the container that holds the feature history of your model.

[freedman]

I think some of the confusion is self-inflicted because of program development over the years. FreeCAD starts at the Body level instead of the Part or Assembly level so folks start out thinking they are designing some kind of assembly because there is no obvious structure. Solidworks had the same problem and solved it by asking the user a question, Part or Assembly.

I like the Body concept as one piece because I know it's one small piece of the unit. Maybe it's time to start Part Design with a default Part container, then it will be obvious there is more to consider when building a multi-part unit.

I also think our future is 3D printing (in some form) and having the body as one piece might be on the leading edge of what should be done. When 3D printing there are big advantages to the current Body, it can be printed just as it is, it doesn't have to be taken apart and turned into multiple files. It's perfect the way it is.

[rstech]

It all depends on "design intent". For example if you have a PCB with a copper layer and want to "etch" the copper into separate spurs, you want to remain the spurs in one part with one material. So the part (copper sheet) contains several bodies (spurs).

[HarryGeier]

Honestly..

a PCB Board is so far away from PART DESIGN´s usage intentions as a smartphone is from an iceberg.

For such PART and DRAFT are the proper approaches. You would import the shapes from the EDA Software anyway.

In that scenario , if using PD, the board, each signal and each other copper element would be a BODY on it´s own.

[chrisb]

It would be far more sensible to name it according to its fundamental purpose.

Very well said!

[openBrain]

According to https://www.freecadweb.org/wiki/PartDesign_Workbench :

• Part WB => CSG WB
• PartDesign WB => Parametric WB

?

[HarryGeier]

According to https://www.freecadweb.org/wiki/PartDesign_Workbench :

• Part WB => CSG WB
• PartDesign WB => Parametric WB

?

There has already been a discussion about a year ago..
i remember that an Argument was : Part , i.e. CSG is also Parametric
so CSG WB vs OCC WB .. no one would understand that ..

[chrisb]

And vice versa you can work with the primitives inside of PartDesign in a CSG manner.

[freedman]

We also want part numbers assigned to everything and tracked in the future bill-of-materials manager. The current Body structure works well with one body, one part number. For multiple objects in one body, how are part numbers assigned and revs to be handled?

If anyone knows; What is the maximum character length of the Body name?

[wandererfan]

If anyone knows; What is the maximum character length of the Body name?

Object names are based on C-style character strings, so the upper limit is probably 64K bytes if there is sufficient available memory. If the string is encoded in Utf8, the number of characters could be less than that since some characters will occupy multiple bytes.