beginners ignorance ?

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rmcveigh
Posts: 8
Joined: Thu Oct 10, 2019 9:49 am

beginners ignorance ?

Postby rmcveigh » Thu Oct 10, 2019 10:54 am

Hi there, and may I apologize in advance for my obvious lack of knowledge in this field, having just started working with Freecad.
I am attempting to design a replacement for a long extinct cover for a foot synthesizer, and have thus far succeeded in sketching the basic body, making a pad and performed one stage of pocket to start removing areas. However as I attempt to do another pocket, and have started a sketch, the program has now placed my sketch in a different plane/axis to the original which means that a) I cannot view the sketch parameters in relation to the face I wish to place the sketch on and b) the sketch, once started, appears to be in a different dimension wherein if I move it into the position it needs to be, it disappears within the pad ?
Ray

OS: OS X El Capitan (10.11)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16131 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.3)
Hash: 3129ae4296e40ed20e7b3d460b86e6969acbe1c3
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)
retry.FCStd
(30.53 KiB) Downloaded 14 times
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PrzemoF
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Re: beginners ignorance ?

Postby PrzemoF » Thu Oct 10, 2019 12:29 pm

Welcome to the forum and thank you for providing the version info.

It it what you need?
https://peertube.social/videos/watch/b1 ... ac8e85adbc
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pl7i92LCNC
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Location: RLP DE

Re: beginners ignorance ?

Postby pl7i92LCNC » Thu Oct 10, 2019 1:14 pm

somthing like moog taurus 1-3
there are still replacements online
vocx
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Re: beginners ignorance ?

Postby vocx » Thu Oct 10, 2019 3:56 pm

rmcveigh wrote:
Thu Oct 10, 2019 10:54 am
...However as I attempt to do another pocket, and have started a sketch, the program has now placed my sketch in a different plane/axis to the original ...
This sounds like the topological naming problem. Essentially, don't place sketches on faces as this is subject to break once you start modifying the underlying object.

Attach the sketch to the body's main planes, or use datum objects as reference.
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rmcveigh
Posts: 8
Joined: Thu Oct 10, 2019 9:49 am

Re: beginners ignorance ?

Postby rmcveigh » Thu Oct 10, 2019 5:12 pm

pl7i92LCNC wrote:
Thu Oct 10, 2019 1:14 pm
somthing like moog taurus 1-3
there are still replacements online

exactly ! its for a Moog Taurus 1, but I've looked everywhere and have spoken with Syntaur, who have what little replacement spares are still around for this model and they couldn't help...if you have a link to any I'd be hugely grateful !
chrisb
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Re: beginners ignorance ?

Postby chrisb » Thu Oct 10, 2019 5:14 pm

vocx wrote:
Thu Oct 10, 2019 3:56 pm
This sounds like the topological naming problem.
This is a different issue. In ReportView you can see a message: The graph must be a DAG. You can have a look at the Std DependencyGraph which looks like this:
Snip macro screenshot-0c39cc.png
Snip macro screenshot-0c39cc.png (19.53 KiB) Viewed 558 times
The red arrow at Sketch001 shows the issue. That Sketch depends somehow on itself.

You can repair it with the following procedure:
- Select Pad in the tree to the left and make it visible
- select the top face (I will come back to this later considering vocx's proposal)
- select Map sketch to face from the Sketcher menu or click the corresponding icon.
- select Sketch001 and confirm with Ok.
- Right click on the filename and select "Mark to recompute"
- recompute

Now your Dependency graph looks ok. And you can map the last sketch and edit it to lie on the right face in the right orientation.

Now to the increase robustness: Mapping sketches to faces can all of a sudden change the face of attachment if you edit something in an earlier step, due to internal renumbering.
Robustness increases, if you attach sketches to the main planes (or later, if you know FreeCAD better, to DatumPlanes). To do so e.g. for Sketch001, you can:

- select Origin in the tree
- make it visible and select XY-plane
- attach Sketch001 as before
- the sketch lies now on the bottom and the pocket has seemingly vanished, but looking from the back you still see the outline
Snip macro screenshot-4c7c08.png
Snip macro screenshot-4c7c08.png (1.6 KiB) Viewed 558 times
- double click on Pocket and check "Reversed" and set the type to "Through all"
- the start of the pocket has now to be changed to the plane where it ended before all these changes (3.4mm):
- select Sketch001 and click in the DataTab on AttachmentOffset and then on the three-dots-button appearing to the right
- enter 3.4mm for the z component, which is where the pocket should end

I attached the file in this state. Continue in the same way with the other sketches and pockets.
Attachments
retry_cb.FCStd
(26.73 KiB) Downloaded 9 times
vocx
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Re: beginners ignorance ?

Postby vocx » Thu Oct 10, 2019 6:36 pm

chrisb wrote:
Thu Oct 10, 2019 5:14 pm
This is a different issue. In ReportView you can see a message: The graph must be a DAG. You can have a look at the Std DependencyGraph which looks like this:
This looks like the topological naming problem. When you have this problem it's not uncommon to end up with cyclic dependencies and broken dependency graphs. Basically, the topological naming is the cause, while the dependency graph shows the effect.
Always add the important information to your posts if you need help.
To support the documentation effort, and code development, your donation is appreciated: paypal.
chrisb
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Re: beginners ignorance ?

Postby chrisb » Thu Oct 10, 2019 7:17 pm

Can you pin it down how this happens? Perhaps at least the cyclic dependency can be prohibited.
rmcveigh
Posts: 8
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Re: beginners ignorance ?

Postby rmcveigh » Fri Oct 11, 2019 11:39 pm

chrisb wrote:
Thu Oct 10, 2019 5:14 pm

You can repair it with the following procedure:
- Select Pad in the tree to the left and make it visible
- select the top face (I will come back to this later considering vocx's proposal)
- select Map sketch to face from the Sketcher menu or click the corresponding icon.
- select Sketch001 and confirm with Ok.
- Right click on the filename and select "Mark to recompute"
- recompute

This now works and I am making really great strides, thank you immensely chrisb ! Unfortunately having gotten right to the end of the process, I hit save and am confronted with the attached error message...

"Failed to open file: final draft.FCStd.f07cad31-255c-4678-8a03-120e702a35ec

Panicked after several hours of calculating and editing , for fear of losing the details, I have screenshot each step w/every measurement and constraint shown, and closed & quit the app, reopened & repeated the whole design, albeit somewhat faster as I have all the details to hand, and it does the exact same..I try hitting save after my first sketch..same thing.
It was not doing this earlier, obviously, as I was able to open and send the original work file to this post, so I am baffled as to why it's doing this now ?
I have tried to quit, close and reboot the Mac, same outcome once I reopen Freecad and start new project etc...
chrisb
Posts: 24399
Joined: Tue Mar 17, 2015 9:14 am

Re: beginners ignorance ?

Postby chrisb » Fri Oct 11, 2019 11:47 pm

I have no idea what happens there. Can you open/save other files? Can you "Save as"?