What is the concept of a Body in FreeCAD?

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nithinrao
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What is the concept of a Body in FreeCAD?

Post by nithinrao »

I was trying out something today and couldnt not understand the concept of a Body in FreeCAD.

Why isnt two pad features not connected to each other.(Not connected yet in the model, the features to follow will connect them). For example, In the Fillet tool in Part we can only get the list of edges of one of the bodies not both.

Also in the following image. The first pad is in the z direction, then the green plane is used as the sketch plane to make another rectangle in air. The problem is it can be extruded only if there is an overlap/touch with the previous 1st Body.

http://postimg.org/image/fmjn6jdj5/

Another error occurred with the display however it was not reproducible. This one.

http://postimg.org/image/cn2je12g7/
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jriegel
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Re: What is the concept of a Body in FreeCAD?

Post by jriegel »

I asume you use the 0.13?

There is at the moment a Solid rule, which assure one solid body as an outcome of PartDesign.
Stop whining - start coding!
nithinrao
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Re: What is the concept of a Body in FreeCAD?

Post by nithinrao »

OS: Ubuntu 13.04
Platform: 64-bit
Version: 0.14.2136 (Git)
Branch: master
Hash: 2e31e177a8b03d9a58b4a35ddf19904e4dfc56bc
Python version: 2.7.4
Qt version: 4.8.4
Coin version: 3.1.3
SoQt version: 1.5.0
OCC version: 6.5.0

This is my FreeCAD version.
triplus
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Re: What is the concept of a Body in FreeCAD?

Post by triplus »

Try to imagine it like this you are trying to create 2 independent solids/parts i don't know what is the most correct term and have one relation between them and that relation is the sketch on the face of the first solid/part that serves as the base for the second solid/part.

You are basically trying to create assembly of two solids/parts tight together by one relation. This will be the job of new assembly workbench in the future (adding relations) for now you have to create new independent sketch for second solid/part and position solids/parts where you would like them to be in 3D space from property view and not yet with relations this is not supported yet.

For now create 2 solids/parts with independent sketches as their base and position them manually from properties view to get representation of assembly but without relations. After new assembly workbench lands then we will be able to start talking about assemblies based upon relations between solids/parts...
nithinrao
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Re: What is the concept of a Body in FreeCAD?

Post by nithinrao »

That idea of building multiple bodies in a single window is good. But do we have control over which features belong to which body?

I'm sorry for asking the question because i haven't tried the branch with assembly module yet. I have another question but probably I should check out the branch which has the developed assembly, before i ask it.
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jriegel
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Re: What is the concept of a Body in FreeCAD?

Post by jriegel »

At the moment Jan develop in his Branch a PartDesign which features a special Object "Body" which will group the Features and modeling-history of on solid body underneath. That will also lead to the merge of the merge of the development assembly module.
As triplus said, it will manage the relation and positioning of the bodies to each other..
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triplus
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Re: What is the concept of a Body in FreeCAD?

Post by triplus »

That idea of building multiple bodies in a single window is good.
Usually no. Imagine you would later on use assembly operations on 2 solids/parts that share the same sketch...
But do we have control over which features belong to which body?
Yes exactly this is one issue if you have multiple solids/parts in one group with common properties. There might be procedure implemented to create 2 Pads in one Sketch for example and the outcome would be 2 solids/parts and probably they could have individual properties/control...

But bottom line you would try to do something like that because you would like to control relations between 2 solids/part wouldn't you? And if that is true this is the job for assembly workbench and not for the Sketcher!
nithinrao
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Re: What is the concept of a Body in FreeCAD?

Post by nithinrao »

triplus wrote:
That idea of building multiple bodies in a single window is good.
Usually no. Imagine you would later on use assembly operations on 2 solids/parts that share the same sketch...
But do we have control over which features belong to which body?
Yes exactly this is one issue if you have multiple solids/parts in one group with common properties. There might be procedure implemented to create 2 Pads in one Sketch for example and the outcome would be 2 solids/parts and probably they could have individual properties/control...

But bottom line you would try to do something like that because you would like to control relations between 2 solids/part wouldn't you? And if that is true this is the job for assembly workbench and not for the Sketcher!
Well But you can also not say it is a bad Idea. The Common sketch might be the skeleton model for both the parts. So its necessary, in reality very necessary. Relations do exist between parts depending on how they are assembled.
triplus
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Re: What is the concept of a Body in FreeCAD?

Post by triplus »

The Common sketch might be the skeleton model for both the parts. So its necessary, in reality very necessary.
Common sketch would only limit you to one 2D plane and relations that can exist on it. Assembly workbench doesn't limit you in this way.
Relations do exist between parts depending on how they are assembled.
Exactly and that will be the job of new assembly workbench. It will help to determine this relations.

P.S. Basically you are trying to do assemblies (relation based) but we are just not there yet. Sketcher is not the place to solve this it's assembly workbench job to do this!
triplus
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Re: What is the concept of a Body in FreeCAD?

Post by triplus »

Take a look at this video:

viewtopic.php?f=10&t=1523&p=12299#p12299
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