week one of learning parametric CAD

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Shalmeneser
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Re: week one of learning parametric CAD

Post by Shalmeneser »

PartDesign wb :
Part is a container for Bodies, keeping everything tidy. It is optionnal.
Body is a container for chronological constructions working on the same connected object automatically-fusing.
chrisb
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Re: week one of learning parametric CAD

Post by chrisb »

batt wrote: Thu Sep 23, 2021 1:56 am A part in my world for 65 years was only a compleated single entity ... several parts made up a part assy or assy ... or many part assy made up an assy.
Usage of the word "Part" is indeed rather problematic, because it has already different meanings in FreeCAD and some more from everybody's common language knowledge may be added.

What you describe as a part is indeed a body: a single solid.
A body is made of features, which are adding or subtracting material from the solid. Imagine your first pad (or a primitive) as a lump of clay to which you can add more clay or take material away.

Multiple bodies can be placed in a Part container. I purposely add the word "container" to distinguish it from the things below. A Part container is what you call an assembly. You can move the container and everything inside will move with it.

Then we have the Part workbench, which historically is the oldest way to create what is called in FreeCAD a Part, which may explain the unprecise usage of words. These Parts are usually solids too, but they are neither limited to single solids, nor to be solids at all, they can be surfaces too.
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batt
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Re: week one of learning parametric CAD

Post by batt »

Yes, I am understanding what freecad is about ... but am so used to thinking a part as a part, not a container.
A body I would never ever think of it as basically a construction area.
Just have a hard time getting my head around what these names actually mean in freecad ... I do not think anyone in the drafting world would think of a part as a container ... body would equate to construction levels in my would ... not complaining ... I will get use to it.
Have not read std part properly yet but that would be just a single part that is made to iso ansi din standards like a ball race or m6 screw but in freecad it seems to be what I would think was an assy or part assy. ... really should not say too much as I admit have not read the documentation well enough.

batt
Bance
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Re: week one of learning parametric CAD

Post by Bance »

You would do well not to compare 3D cad to traditional drafting, they are very different beasts.

In these days of CNC/CAM drafting is an almost insignificant aside to a fully parametric 3D model.

You will not be drawing parts, but creating models. :D
chrisb
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Re: week one of learning parametric CAD

Post by chrisb »

The word "Standard", or rather its shortcut "Std" is there rather for another technical reason. It means it is not Workbench dependent, but always globally available in the program, like Std DependencyGraph which is no standard at all.
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user1234
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Re: week one of learning parametric CAD

Post by user1234 »

Hello!
batt wrote: Thu Sep 23, 2021 1:56 am I find it a bit strange in trying to understand parts and body ... have been drafting for 65 years started out with pencil on paper...then ink on plastic ... and now computers.

A part in my world for 65 years was only a compleated single entity ... several parts made up a part assy or assy ... or many part assy made up an assy.

So I really have a hard time understanding what is meant by a part is a container they hold bodies ...
A minimal example: welded parts.
Here a hydraulic cylinder pipe, which have
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- a pipe, which is a body
- a cover, which is a body
- a flange, which is a body
- studs, which are bodies
- and welding seams, which are bodies.

Also the materials are different, so i must find at least one kind of separation, in that case the body type.

But as a whole, it is one part, since it can not dismounted nondestructive, at least that is my definition what a part means. Also i (must) move that part as a whole in CAD, since i want not move every part separate, and give that part some data properties.

A steel constructor will maybe define this example as assembly as his profession is welding. So everybody must define himself his definitions, but at least there must be sort of separation since some people need this for construction in CAD.

Also just said, that if you save the files in a PDM or ERP system, you can separate them and handle them also separate, which is pretty often important.

Greetings
user1234
batt
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Re: week one of learning parametric CAD

Post by batt »

user 1234
In my industry in Australia, we would call that an assy ( if it is fully compleated ) and all the pieces would be parts whether they are screwed welded or glued together.
batt
user1234
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Re: week one of learning parametric CAD

Post by user1234 »

One time in my life i worked with Australians and they also separated that (in machine engineering industry).

Also if then, many does differ.

Greetings
user1234

edit: added text (blue)
batt
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Re: week one of learning parametric CAD

Post by batt »

If I want to learn freecad have to accept their terminology.
batt
user1234
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Re: week one of learning parametric CAD

Post by user1234 »

This is not FreeCAD specific!

Greetings
user1234
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