Destructive Edits

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Altmaken
Posts: 5
Joined: Mon May 29, 2023 8:59 pm

Destructive Edits

Post by Altmaken »

I'm fairly new to FreeCAD so bear with me...
As I understand it, the latest version -- 0.2 -- allows you to create threaded holes in a part. However, if you sketch a series of circles and then apply the hole command all the circles in that sketch will be the same size of hole regardless of the size of the circle originally sketched.

Therefore, to get multiple sizes of threaded holes in a single object you need to create a new sketch for each desired size.

I created a sketch for my 3/8" threads, another for my 1/4" threads, another for the 3mm, another for the 4mm, and another for the non-threaded slots. Later I wanted to remove three of the 16 1/4" threaded holes. When I deleted them and their constraints I found some of the holes & slots in subsequent sketches were deleted or moved. I can't figure out why.

I'm guessing that because I'm creating multiple sketches on a single part surface they are interfering with each other... perhaps because of using the same external geometry anchor point??

Can anyone tell me what I'm doing wrong?
frcaduser
Posts: 351
Joined: Wed Apr 07, 2021 11:22 pm

Re: Destructive Edits

Post by frcaduser »

Hello,

can you please include the information found by going to Help > About on the top menu.

Also, can you please fill us in on the workbench that you're using for your project (i.e., to understand your
design approach). By the way, a very good workbench for repeating objects is the Lattice2 workbench.
The other is the Draft workbench as they both create arrays of objects.

Design once, create an array of the object to make multiple copies of it - since as you stated you use the same
object multiple times in the part that you're designing.

Here is a youtube video highlighting some of the features available from the Lattice2 workbench.
https://www.youtube.com/watch?v=ly3lhNZwK3o

Reference the attachment regarding creating an array using the Draft workbench.

frcaduser
Attachments
3D_Object_Array_Placement_and_Directional_Control.pdf
(259.03 KiB) Downloaded 10 times
chrisb
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Re: Destructive Edits

Post by chrisb »

Altmaken wrote: Mon May 29, 2023 9:21 pm Therefore, to get multiple sizes of threaded holes in a single object you need to create a new sketch for each desired size.
That's not bad to keep the sketches simple.
Later I wanted to remove three of the 16 1/4" threaded holes. When I deleted them and their constraints I found some of the holes & slots in subsequent sketches were deleted or moved.
It's a classic: don't sketch on faces, or you are trapped by the topological naming problem.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
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M4x
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Location: Germany

Re: Destructive Edits

Post by M4x »

I highly recommend to read this part of the wiki: Feature_editing#Advice_for_creating_stable_models
drmacro
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Re: Destructive Edits

Post by drmacro »

M4x wrote: Tue May 30, 2023 9:50 am I highly recommend to read this part of the wiki: Feature_editing#Advice_for_creating_stable_models
But, read it carefully. And, DON"T take away that Datum planes fix TNP.

The example used mentions, but does not emphasize, that attaching Datum planes to generated geometry is no better than attaching sketches to generated geometry.

Attach sketches to base planes and use Attachment offset to reduce the risk of TNP.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
Altmaken
Posts: 5
Joined: Mon May 29, 2023 8:59 pm

Re: Destructive Edits

Post by Altmaken »

frcaduser wrote: Tue May 30, 2023 3:58 am Hello,

can you please include the information found by going to Help > About on the top menu.

Also, can you please fill us in on the workbench that you're using for your project (i.e., to understand your
design approach).
OS: macOS 10.16
Version: 0.20.2.29603 (Git)
Build type: Release
Python 3.10.8, Qt 5.15.4, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3

As a new user I use Sketch & Part Design almost exclusively. I haven't learned the others.
Altmaken
Posts: 5
Joined: Mon May 29, 2023 8:59 pm

Re: Destructive Edits

Post by Altmaken »

FYI -- here's the finished design that I'm trying to edit.
SR-plate.pdf
(60.12 KiB) Downloaded 15 times
Altmaken
Posts: 5
Joined: Mon May 29, 2023 8:59 pm

Re: Destructive Edits

Post by Altmaken »

M4x wrote: Tue May 30, 2023 9:50 am I highly recommend to read this part of the wiki: Feature_editing#Advice_for_creating_stable_models
I'm not sure I understand all of this yet but, once I do, it seems that it'll fix my issues.

Thanks
frcaduser
Posts: 351
Joined: Wed Apr 07, 2021 11:22 pm

Re: Destructive Edits

Post by frcaduser »

Altmaken wrote: Tue May 30, 2023 1:52 pm As a new user I use Sketch & Part Design almost exclusively. I haven't learned the others.
It will help you in the long run if you learn other workbenches as each workbench offers unique tool sets and tools that perform
specific functions ... you don't need to learn all of them necessarily but learning a few others will help you to get you up and running.
You can think of all of the workbenches as being different units within a large company (FreeCAD). One workbench can be the
accounting dept., another the woodshop dept., another the machine shop dept., etc. Each is unique but if you look at it in these
terms, it would not make sense to go the accounting dept. if a wrench is what you need. In other words, some workbenches offer
tools that might be better tailored for specific tasks/functions verses others. They might also have a way of performing functions
more elegantly and efficiently.

fyi ..., it also helps to watch youtube videos and following along recreating some of the objects to get you familiar with some of the
tools available in other workbenches.

Just a heads up from another relatively new user.

frcaduser
Altmaken
Posts: 5
Joined: Mon May 29, 2023 8:59 pm

Re: Destructive Edits

Post by Altmaken »

I was looking through the task tree and discovered my first sketch -- the basis of my part -- wasn't fully constrained. I corrected this.

I was then able to go through each sketch a repair those that had lost reference points. Once fixed I could then go back and make the edits I needed.

Thanks for the help and suggestions.
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