using FCGear to cut a gear inside a gear

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domad
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Re: using FCGear to cut a gear inside a gear

Post by domad »

enmane wrote: Fri Jan 14, 2022 4:35 pm ....
Domad,
I noticed that you did not create a Part or Body. What don't I understand about FreeCAD that it was so obvious for you? :-) It seemed as soon as I moved those parts out of the Body and out of the Part then it worked fine. Where do I read to get up to speed on recommendations between types of parts/bodies/entities and which workbenches work with them? Note: I have done A LOT of reading over the past 3 weeks and it still isn't clear.

Can I ask that you scale the center object as I go to Draft WB, create a clone, then click on the clone and change the scale from 1.0 to 1.05 and it doesn't take - it reverts back to 1
....
Very, very, very, very ... briefly:
Wb Part:
- creates complex objects starting from pre-set 3D objects called "Primitive or basic shapes" through the interaction with the parameters in the properties, together with the Boolean functions of union, difference and intersection;
- creates objects starting from closed flat geometries (closed polylines or wires or faces) created through the use of the "Draft" Wb or through the use of the "Sketcher" Wb, together with the use of classic 3D tools: extrusion, loft , revolution and sweep.
this work environment is complemented by many other modeling functions that speed up, enhance and refine modeling.
Wb "Part Design":
- creates objects properly defined "bodies" starting from closed flat geometries generated with "Sketcher" (with which it works in synergy) obtained through geometric and dimensional constraint functions.
The objects or bodies that must be modeled with this Wb are intended as unique or rather monolithic.
They develop, through the progressive interaction on the faces already created, in continuity giving rise to a single body or object, for example, a body obtained by fusion; therefore, there must always be contiguity or contact between the volumes that will be modeled; the presence, in a body, of detached or discontinuous components or volumes is not permitted.
This work environment is implemented by many other modeling functions, some similar (not to say the same or having the same effects) to those already mentioned in Wb "Part", which speed up, enhance and refine the modeling.
The modeling functions of the two Wbs (Part and Part Design) being, in some ways, very similar, often lead newbies to mistakenly believe that they are "duplicates" and to mix the two types of modeling during the creation phases. , running into reports of errors, inaccuracies and "refusal" to execute certain modeling functions.
The "Draft" Wb is a set of tools for the creation of 2D geometries but also for the transformation operations (movement and rotation) or for the choice of the work plane etc., in short, a "2D cad".
Obviously all the Wb (not only those already mentioned) available in FreeCad, can act synergistically and simultaneously in a single project by modeling any shape or object or assemblies of objects to form a unit of overall parts such as a machine, a house , a city etc.
After this very short, incomplete and insufficient introduction, in addition to what has already been posted by @TheMarkster, returning to the problem of resizing we can add:
Wb "Draft"
- you can resize the clone from the properties tab -> "Scale" parameter.
To create a copy you can use the classic keyboard shortcuts or copy-paste contextual menu, or the menu -> edit -> "Duplicate selection" button;
Or, again (without creating the clone), by selecting the gear you can use the scaling function:
- "Scale" button
or also
- menu -> "Modification" -> "Scale"
I hope the translation was effective and understanding enough.
You just have to try all the various techniques enunciated. :)
enmane
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Re: using FCGear to cut a gear inside a gear

Post by enmane »

Thanks Domad - that was excellent. Is that captured anywhere in a FreeCAD textbook or wiki? That's the best I've seen so far.

That said, the way I got scaling to work was
1) Drop to Draft
2) Make a clone 1
3) When trying to scale clone 1 - it kept reverting to [1 1 1 ] no matter the scaling facto
4) Created a copy of Clone 1 with "clone" box checked to create Clone 2
5) Scaling of Clone 2 seemed to work

I'll continue to dig but wanted to get back to you to thank you for the help. I was able to print the gear, insert the driving gear, and the shredder is up and running again. I will also look to recreate the model as I had some shaving to do to make it all work. I'm also looking to learn FreeCAD at a fundamental level so I can teach my children properly.

Best wishes all! Stay safe in 2022
TheMarkster
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Re: using FCGear to cut a gear inside a gear

Post by TheMarkster »

enmane wrote: Sat Jan 15, 2022 4:46 pm Thanks Domad - that was excellent. Is that captured anywhere in a FreeCAD textbook or wiki? That's the best I've seen so far.

That said, the way I got scaling to work was
1) Drop to Draft
2) Make a clone 1
3) When trying to scale clone 1 - it kept reverting to [1 1 1 ] no matter the scaling facto
4) Created a copy of Clone 1 with "clone" box checked to create Clone 2
5) Scaling of Clone 2 seemed to work

I'll continue to dig but wanted to get back to you to thank you for the help. I was able to print the gear, insert the driving gear, and the shredder is up and running again. I will also look to recreate the model as I had some shaving to do to make it all work. I'm also looking to learn FreeCAD at a fundamental level so I can teach my children properly.

Best wishes all! Stay safe in 2022
I noticed a difference between scaling and offsetting using WireFilter. Perhaps the reason to need to do some shaving was that difference.

Using Offsetting:
Snip macro screenshot-63f618.png
Snip macro screenshot-63f618.png (61.86 KiB) Viewed 913 times
Using scaling:
Snip macro screenshot-f732cb.png
Snip macro screenshot-f732cb.png (57.32 KiB) Viewed 913 times
enmane
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Joined: Fri Jan 14, 2022 2:11 pm

Re: using FCGear to cut a gear inside a gear

Post by enmane »

Hi All,
I'd like to make some modifications of the shape to the inner gear as it isn't quite like the one that comes from the offset. Is there a way to take the wirefilter image to the Draft workbench and then put fillets on it and then export back to a new face that I can either pocket in Part Design WB or use as a solid in Part WB?
In short, there are some of those features of the cutout that are interfering with the mating gear so I need to clear them away and have been trying since yesterday unsuccessfully.
Thanks

Here's an example of a shape that I'd like to further cut out after offsetting the wirefilter - unfortunately, in 0.19 it doesn't work correctly - how stable is 0.20? Any advice on how to make the cut of Body from Body001 - see file attached - seems HTTP error on uploading and I'll keep trying
Last edited by enmane on Mon Jan 17, 2022 6:38 pm, edited 1 time in total.
TheMarkster
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Re: using FCGear to cut a gear inside a gear

Post by TheMarkster »

Possibly you could create the gears in separate bodies and do the boolean cut on the bodies using Part workbench Cut tool. This way you can fillet the edges of the inner gear as desired prior to doing the offset.
enmane
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Re: using FCGear to cut a gear inside a gear

Post by enmane »

lmk if the file successfully attached - seems it won't

I've tried unsuccessfully for the last couple hours to try and get an FCGear dropped and then try to edit the profile but unsuccessful. It would be great to take a face, drop it to a sketch, then trim and/or fillet some of those lines and then extrude in PD Workbench.

I tried unsuccessfully in Part WB to fillet the faces of the FCGear solid.

I tried many different combinations of clones, copies, shapebinder, etc with no success. I wish there would be some consistency with approach or a great tutorial on how and why one should interact with FreeCAD in a certain way. I'll still hang in there but will also be looking to see what is available to my children through education discounts because if I can't understand the rationale, it'll be hard to explain and for them to understand. I fully understand that, if I was a coder, then this would all be clear to me however this seems to be a common difference in understanding between coders of software and users of software.

- Note: I've been trying all day to upload the file however I continue to get an HTTP error window.
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adrianinsaval
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Re: using FCGear to cut a gear inside a gear

Post by adrianinsaval »

use Draft workbench downgrade tool until you get a wire, then use wire to sketch tool
TheMarkster
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Re: using FCGear to cut a gear inside a gear

Post by TheMarkster »

adrianinsaval wrote: Tue Jan 18, 2022 12:38 pm use Draft workbench downgrade tool until you get a wire, then use wire to sketch tool
This does not work with offsets.
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adrianinsaval
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Re: using FCGear to cut a gear inside a gear

Post by adrianinsaval »

TheMarkster wrote: Tue Jan 18, 2022 4:37 pm This does not work with offsets.
Then first upgrade and then downgrade, of course it won't be a parametric offset anymore
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Re: using FCGear to cut a gear inside a gear

Post by TheMarkster »

adrianinsaval wrote: Tue Jan 18, 2022 4:51 pm
Then first upgrade and then downgrade, of course it won't be a parametric offset anymore
It doesn't work if there are bsplines in the original object, in this case in the gear. I get this error:

Traceback (most recent call last):
File "E:\FreeCAD_0.20.26858_Win-LPv12.5.4_vc17.x-x86-64\Mod\Draft\draftutils\todo.py", line 167, in doTasks
Gui.doCommand(string)
File "<string>", line 1, in <module>
File "E:\FreeCAD_0.20.26858_Win-LPv12.5.4_vc17.x-x86-64\Mod\Draft\draftmake\make_sketch.py", line 308, in make_sketch
nobj.addGeometry(DraftGeomUtils.orientEdge(
TypeError: Unsupported geometry type: Part::GeomOffsetCurve


The Part::GeomOffsetCurve is a special kind of edge, maybe it's new, not sure. Draft To Sketch doesn't work with them. It might be possible to fix by simply treating these types of curves the same way bsplines are treated.
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