Assistance Please - CAD for a 3D Block??

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chrisb
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Re: Assistance Please - CAD for a 3D Block??

Post by chrisb » Fri Nov 20, 2020 6:27 pm

Dougl wrote:
Fri Nov 20, 2020 5:06 pm
your posted example is much appreciated as it helps me work on snapping out of my tendency to think of 3D primitives first when I should be thinking in 2D profiles.
There are several people, especially in the German forum, who are thinking that way too. They use Part workbench only and are happy with it.
You need at least FreeCAD 0.19.23300 to edit my current sketches.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Dougl
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Re: Assistance Please - CAD for a 3D Block??

Post by Dougl » Fri Nov 20, 2020 6:36 pm

Thanks, but it took me a little bit to figure this out. I deleted pocket001(last pocket operation) and I saw no difference, probably because the fillet was no longer computable. Deleting the fillet showed why you pocketed. ie each 3D part's exterior extends within the hole of the other 3D part.

I do get lost on things like why I can delete the first pocket without there being any effect on the fillet but deleting the 2nd pocket(pocket001) triggers issues which would require removing and recreating the fillet. New to GUI CAD and came from spending just a few months with F360.

@chrisb, since I was "happy" doing OpenSCAD for so long I too might remain content in that environment had I not seen how valuable sketching is. So I'm now tainted and am just in the middle between the two mindsets. Working on my inner visioning techniques to see the 2D side of things earlier or with the 3D.
Doug
FreeCAD for Linux
drmacro
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Re: Assistance Please - CAD for a 3D Block??

Post by drmacro » Fri Nov 20, 2020 6:41 pm

Hmm...just FYI.

You can use sketches in Part and Part Design...
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: Assistance Please - CAD for a 3D Block??

Post by chrisb » Fri Nov 20, 2020 8:47 pm

Dougl wrote:
Fri Nov 20, 2020 6:36 pm
@chrisb, since I was "happy" doing OpenSCAD for so long I too might remain content in that environment had I not seen how valuable sketching is. So I'm now tainted and am just in the middle between the two mindsets. Working on my inner visioning techniques to see the 2D side of things earlier or with the 3D.
As drmacro said, sketch+extrude is a powerful instrument in Part too.
I wandered between the two worlds, and finally I'm doing much more in PartDesign.
You need at least FreeCAD 0.19.23300 to edit my current sketches.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
CRMS
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Joined: Sat Nov 14, 2020 1:10 pm

Re: Assistance Please - CAD for a 3D Block??

Post by CRMS » Sat Nov 21, 2020 11:28 am

Bance wrote:
Fri Nov 20, 2020 3:48 pm
In the screenshot above it can be clearly seen that the fillets are outside of the body, and have the Part WB icon Image

and not the PDWB fillet icon. Image

I presume you know how to analyse an example file?
A bit more RTFM for me on the Part and Part Design WBs!!

Analyse an example file? Non. Only started using last week or so. 2D Coreldraw and HullForm for a boat before. Have installed GraphViz to assist? with flow. But not yet sure what the Dependency Graph all means and which order things should be in?? But at least it isn't circular.

20201120DG1.jpg
20201120DG1.jpg (119.19 KiB) Viewed 153 times
Bance
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Location: London

Re: Assistance Please - CAD for a 3D Block??

Post by Bance » Sat Nov 21, 2020 12:24 pm

OK, if somebody posts a file as an example, open it and expand the entire tree, then make everything invisible using the space-bar.

Go to the top of the tree, start with the first sketch (usually Sketch) make it visible using the space-bar, then the first feature

(usually Pad,) continue down the tree with each sketch and feature in turn. In this way you can see how feature is built on feature,

Pay attention also to the properties tab, here you can find what is attached to what and how, constraints that are based on expressions are coloured blue.

Used in conjunction with the Dependency graph you can find all the relationships in your model. :)
Dougl
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Joined: Thu Oct 01, 2020 6:08 pm

Re: Assistance Please - CAD for a 3D Block??

Post by Dougl » Sun Nov 22, 2020 8:02 pm

Bance wrote:
Sat Nov 21, 2020 12:24 pm
OK, if somebody posts a file as an example, open it and expand the entire tree, then make everything invisible using the space-bar.

Go to the top of the tree, start with the first sketch (usually Sketch) make it visible using the space-bar, then the first feature

(usually Pad,) continue down the tree with each sketch and feature in turn. In this way you can see how feature is built on feature,

Pay attention also to the properties tab, here you can find what is attached to what and how, constraints that are based on expressions are coloured blue.

Used in conjunction with the Dependency graph you can find all the relationships in your model. :)
A much better technique than I was using, ie deleting features and looking at things which were left. I tried your posted technique on this project and it was a more elegant way of showing what's going on. Thanks!
Doug
FreeCAD for Linux
drmacro
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Re: Assistance Please - CAD for a 3D Block??

Post by drmacro » Sun Nov 22, 2020 8:16 pm

Dougl wrote:
Sun Nov 22, 2020 8:02 pm

A much better technique than I was using, ie deleting features and looking at things which were left. I tried your posted technique on this project and it was a more elegant way of showing what's going on. Thanks!
I would offer, that this is a great way to understand what others have done.

But, in some cases it is easier to understand by removing things from the bottom up. In such cases I avoid saving and close, then reopen the original. And work my way up the feature tree.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
Dougl
Posts: 39
Joined: Thu Oct 01, 2020 6:08 pm

Re: Assistance Please - CAD for a 3D Block??

Post by Dougl » Sun Nov 22, 2020 11:51 pm

drmacro wrote:
Sun Nov 22, 2020 8:16 pm
Dougl wrote:
Sun Nov 22, 2020 8:02 pm

A much better technique than I was using, ie deleting features and looking at things which were left. I tried your posted technique on this project and it was a more elegant way of showing what's going on. Thanks!
I would offer, that this is a great way to understand what others have done.

But, in some cases it is easier to understand by removing things from the bottom up. In such cases I avoid saving and close, then reopen the original. And work my way up the feature tree.
That's what I did when I'd asked why the 'extra' pockets and the funny thing is I didn't remove the fillet thinking it wouldn't be effected or effect anything so I removed the pocket001 and it would not rerender the object to show the top part interfering inside the hole of the lower revolved part. Was strange but if I only removed the top pocket(pocket) then the object was rerendered and the incursion of the lower revolve was visible in the hole. But using the turn everything off and walk down the tree worked perfectly. Going forward I will keep both techniques in mind but start with the less destructive method first. :-)
Doug
FreeCAD for Linux
drmacro
Posts: 2361
Joined: Sun Mar 02, 2014 4:35 pm

Re: Assistance Please - CAD for a 3D Block??

Post by drmacro » Mon Nov 23, 2020 12:04 am

fillets in the tree lower than where you change or delete are almost guaranteed to fail since deleting above will delete or rename the geometry the fillet was attached to.

so to use the delete method you have to remove the fillets (or chamfers) before anything above them in the tree.

changes above a fillet or chamfer can also make the fillet fail because the edge/face can no longer support the feature. for example, if 10mm face is reduced to .5 mm and the fillet was specified as 2mm, then fillet will fail.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."

My beginners, written treatise: Learning FreeCAD
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