Using Git for OpenSCAD and 3D Printing

Using Git for OpenSCAD and 3D Printing

[Mr. Sandor Kunyik]

Greetings,

If you were to design a new workflow, what key observations would you 
make in regards to OpenSCAD scripts?

As a quick illustration: I have a model with cavities to hold hex bolts 
and nuts. I fine-tuned the model to print on PrinterA, using FilamentA, 
SettingsA. Once in "production" I need to "freeze" all relevant scripts, 
especially when using multi-file structure. If the modules receive 
parameters I need to "remember" those parameters (such as the radius for 
the hex, and the dept of the cavity), and if they use hard-coded values 
I must remember not to change them. Otherwise I cannot repeatedly print 
the same model.

Now imagine this for the entire standard set of hex bolts - each of 
these were fine-tuned, test-printed and verified.
The rationale behind this to guarantee that the models trying to conform 
to a standard (such as ASME B18.3) stay put, while models receiving 
non-standardized sizes such as Nylon 6/6/ (which have bigger hex heads) 
stay separated, and tweaked to work with each supplier.

My question is, should I just "hardcode" everything, set up forks or 
branches for all past scenarios? So far I only have a few dozen models 
and I'm already having a hard time finding models I printed and used in 
the past, to print again. How do I structure all this?

I am a mechanical engineer not a coder, new to all these. Maybe git or 
revision control is not the correct tool for this job?

-- 
Thanks for your time reading,
Sandor

Re: Using Git for OpenSCAD and 3D Printing

[Philip Oakley]

Hi Sandor

I haven't used OpenSCAD but I thought it worth mentioning some personal
points about using Git for Engineering products, where variants
proliferate and build-products must be  versioned.
 I had a go with FreeCAD a few years ago to create an insulating spacer
that the mech eng had forgotten...

On 05/01/2021 09:57, Mr. Sandor Kunyik wrote:
> Greetings,
>
> If you were to design a new workflow, what key observations would you
> make in regards to OpenSCAD scripts?

I'm sure that git is able to store and version all the scripts and
products, but it does need a vision about how to present the
organisation of the scripts and products, especially for engineered
items. Remember that software version control is just drawing office
procedure with the hard stuff ripped out ;-) [1]
>
> As a quick illustration: I have a model with cavities to hold hex
> bolts and nuts. I fine-tuned the model to print on PrinterA, using
> FilamentA, SettingsA. 

Is the fine tuning done via the scripts, or is it manual. If it is the
latter then it will need the user to record in the commit message for
the revision the various what/why/how aspects that aren't obvious from
the 'diff'. Does OpenSCAD have an informative 'diff' capability? If it
is just a 'compile for printerA using known-tool' then it could be an
automated commit message as you are storing a build product (If it was
regular software it's likely it's a binary..)

> Once in "production" I need to "freeze" all relevant scripts,
> especially when using multi-file structure. If the modules receive
> parameters I need to "remember" those parameters (such as the radius
> for the hex, and the dept of the cavity), and if they use hard-coded
> values I must remember not to change them. Otherwise I cannot
> repeatedly print the same model.

So these parameters are essentially a 'configuration file' (inc. the
hard coded values). If you auto generate such a file then it can easily
be stored within revision (commit) - It is important that the scripts
should be able to work directly from that config file (idempotent [2])

>
> Now imagine this for the entire standard set of hex bolts - each of
> these were fine-tuned, test-printed and verified.
A library? Hence a sub-module perhaps. 
> The rationale behind this to guarantee that the models trying to
> conform to a standard (such as ASME B18.3) stay put, while models
> receiving non-standardized sizes such as Nylon 6/6/ (which have bigger
> hex heads) stay separated, and tweaked to work with each supplier.
A configurable library item? Tricky. I remember a project that need to
change 20,000 drawing because they changed the paint colour (green to
grey), and then the next major order was in the old colour! In software
terms its like 're-skinning' a GUI, but worse.
More likely you'll have a separate sub-module-library for these
'specials' where the source part is cherry-picked (give give a backward
textual reference) and then modified locally giving git level
traceability. 
>
> My question is, should I just "hardcode" everything, set up forks or
> branches for all past scenarios? So far I only have a few dozen models
> and I'm already having a hard time finding models I printed and used
> in the past, to print again. How do I structure all this?

The hard part is to be both the 'design authority' that signs off the
'release' and also the day to day designer trying things where it's a
'fingers crossed' hope that this 3d print run will actually produce what
you want and expect, but mainly it's a case of realising the mistake and
cycle it around.
You should at least use tags for the good release commits, to make them
easy to find.
>
> I am a mechanical engineer not a coder, new to all these. 
I feel you pain. Some of the above may be more suited for those who
actually design and contribute OpenSCAD, rather that a user getting
started.
> Maybe git or revision control is not the correct tool for this job?
>
As an ME you will know that without [good] revision control the world
falls apart for anything other than bespoke item home jobs!

Git is great because it give you full control, and local storage,
without taking up too much room.
Git is a problem because it gives you too much control and too much
choice. Start simple, be open to the 'mind-shift'.

Add any (i.e. more) files that you use to Git. Remove them (one at a
time) when you stop using them. They will still be in the history!

Commit often: including halfway through a change - you know you will add
more and then more, then more tweaks before you print - have a commit
for each. I.e. distinguish between 'Printing' runs, and the act of
'visualising the part' in the OpenSCAD viewer - both steps get a commit,
with concise description. (probably every 5 minutes or less!)

Use the 'git gui' and 'gitk' to visualise how you have developed and
progressed. (or a GUI of your choice -> CAD people are NOT terminal
people!!)

Git unfortunately lacks a short command to allow you to park a completed
items onto a 'Completed' branch that's just an easy quick way of seeing
those finished items (Git has the view that they [old software versions]
are 'gone/left behind', with just a few v# tags), so I don't have any
great solution for that.
If you have concise commit subject titles and messages, then it's easier
to search history for "print: insulating spacer widget v2.1" (and before
that "visualise: insulating spacer widget v2.1a", 1b, 1c, 1d, 1e...).
You may want to allow-empty commits for ease of recording!

Hope that helps.

[1] Drawing Office procedures allow for non perfect machining, serial
numbering, etc. Software generally asserts perfect replication,
repeatability and machining.
[2] https://en.wikipedia.org/wiki/Idempotence
[3] concise: adjective - giving a lot of information clearly and in a
few words; brief but comprehensive. "a concise account of the country's
history" (Git: without repeating the obvious changes shown in the diff!)

Re: Using Git for OpenSCAD and 3D Printing

[Mr. Sandor Kunyik]

Hi Philip!

Thank you so much for the details! I am going to read this many times 
over the next couple of weeks.
I have advanced on this subject, I now have a federated forum dedicated 
to this at https://hubzilla.factoryfouroh.net, and I have a Gitea 
repository installed - all under YunoHost. I am going to be publishing 
all I print (dimension, material, etc.) OpenSCAD scripts, PNG images, 
printable models (STEP) and maybe even animation - OpenSCAD has some 
basic but functional animation capacity.

I stopped subscribing to the git mailing list as I do not want to 
pollute with newbie questions, but your answer is really valuable to me  
because now I have some idea about how a pro would go about this.
Gitea it is, thanks!

On 2021-01-11 12:28, Philip Oakley wrote:
> Hi Sandor
> 
> I haven't used OpenSCAD but I thought it worth mentioning some personal
> points about using Git for Engineering products, where variants
> proliferate and build-products must be  versioned.
>  I had a go with FreeCAD a few years ago to create an insulating spacer
> that the mech eng had forgotten...
> 
> On 05/01/2021 09:57, Mr. Sandor Kunyik wrote:
>> Greetings,
>> 
>> If you were to design a new workflow, what key observations would you
>> make in regards to OpenSCAD scripts?
> 
> I'm sure that git is able to store and version all the scripts and
> products, but it does need a vision about how to present the
> organisation of the scripts and products, especially for engineered
> items. Remember that software version control is just drawing office
> procedure with the hard stuff ripped out ;-) [1]
>> 
>> As a quick illustration: I have a model with cavities to hold hex
>> bolts and nuts. I fine-tuned the model to print on PrinterA, using
>> FilamentA, SettingsA.
> 
> Is the fine tuning done via the scripts, or is it manual. If it is the
> latter then it will need the user to record in the commit message for
> the revision the various what/why/how aspects that aren't obvious from
> the 'diff'. Does OpenSCAD have an informative 'diff' capability? If it
> is just a 'compile for printerA using known-tool' then it could be an
> automated commit message as you are storing a build product (If it was
> regular software it's likely it's a binary..)
> 
>> Once in "production" I need to "freeze" all relevant scripts,
>> especially when using multi-file structure. If the modules receive
>> parameters I need to "remember" those parameters (such as the radius
>> for the hex, and the dept of the cavity), and if they use hard-coded
>> values I must remember not to change them. Otherwise I cannot
>> repeatedly print the same model.
> 
> So these parameters are essentially a 'configuration file' (inc. the
> hard coded values). If you auto generate such a file then it can easily
> be stored within revision (commit) - It is important that the scripts
> should be able to work directly from that config file (idempotent [2])
> 
>> 
>> Now imagine this for the entire standard set of hex bolts - each of
>> these were fine-tuned, test-printed and verified.
> A library? Hence a sub-module perhaps. 
>> The rationale behind this to guarantee that the models trying to
>> conform to a standard (such as ASME B18.3) stay put, while models
>> receiving non-standardized sizes such as Nylon 6/6/ (which have bigger
>> hex heads) stay separated, and tweaked to work with each supplier.
> A configurable library item? Tricky. I remember a project that need to
> change 20,000 drawing because they changed the paint colour (green to
> grey), and then the next major order was in the old colour! In software
> terms its like 're-skinning' a GUI, but worse.
> More likely you'll have a separate sub-module-library for these
> 'specials' where the source part is cherry-picked (give give a backward
> textual reference) and then modified locally giving git level
> traceability. 
>> 
>> My question is, should I just "hardcode" everything, set up forks or
>> branches for all past scenarios? So far I only have a few dozen models
>> and I'm already having a hard time finding models I printed and used
>> in the past, to print again. How do I structure all this?
> 
> The hard part is to be both the 'design authority' that signs off the
> 'release' and also the day to day designer trying things where it's a
> 'fingers crossed' hope that this 3d print run will actually produce 
> what
> you want and expect, but mainly it's a case of realising the mistake 
> and
> cycle it around.
> You should at least use tags for the good release commits, to make them
> easy to find.
>> 
>> I am a mechanical engineer not a coder, new to all these.
> I feel you pain. Some of the above may be more suited for those who
> actually design and contribute OpenSCAD, rather that a user getting
> started.
>> Maybe git or revision control is not the correct tool for this job?
>> 
> As an ME you will know that without [good] revision control the world
> falls apart for anything other than bespoke item home jobs!
> 
> Git is great because it give you full control, and local storage,
> without taking up too much room.
> Git is a problem because it gives you too much control and too much
> choice. Start simple, be open to the 'mind-shift'.
> 
> Add any (i.e. more) files that you use to Git. Remove them (one at a
> time) when you stop using them. They will still be in the history!
> 
> Commit often: including halfway through a change - you know you will 
> add
> more and then more, then more tweaks before you print - have a commit
> for each. I.e. distinguish between 'Printing' runs, and the act of
> 'visualising the part' in the OpenSCAD viewer - both steps get a 
> commit,
> with concise description. (probably every 5 minutes or less!)
> 
> Use the 'git gui' and 'gitk' to visualise how you have developed and
> progressed. (or a GUI of your choice -> CAD people are NOT terminal
> people!!)
> 
> Git unfortunately lacks a short command to allow you to park a 
> completed
> items onto a 'Completed' branch that's just an easy quick way of seeing
> those finished items (Git has the view that they [old software 
> versions]
> are 'gone/left behind', with just a few v# tags), so I don't have any
> great solution for that.
> If you have concise commit subject titles and messages, then it's 
> easier
> to search history for "print: insulating spacer widget v2.1" (and 
> before
> that "visualise: insulating spacer widget v2.1a", 1b, 1c, 1d, 1e...).
> You may want to allow-empty commits for ease of recording!
> 
> Hope that helps.
> 
> [1] Drawing Office procedures allow for non perfect machining, serial
> numbering, etc. Software generally asserts perfect replication,
> repeatability and machining.
> [2] https://en.wikipedia.org/wiki/Idempotence
> [3] concise: adjective - giving a lot of information clearly and in a
> few words; brief but comprehensive. "a concise account of the country's
> history" (Git: without repeating the obvious changes shown in the 
> diff!)

-- 
Regards,
Mr. Sandor Kunyik
FourOh-LLC Technology Evangelist

Re: Using Git for OpenSCAD and 3D Printing

[Philip Oakley]

Hi Sandor,

Just confirming details for other readers.

On 18/01/2021 06:07, Mr. Sandor Kunyik wrote:
>
> Hi Philip!
>
> Thank you so much for the details! I am going to read this many times
> over the next couple of weeks.
> I have advanced on this subject, I now have a federated forum
> dedicated to this at https://hubzilla.factoryfouroh.net,
the home page is rather bare. Others may find these links better
https://hubzilla.factoryfouroh.net/directory/?f=&keywords=3D-Printing
https://hubzilla.factoryfouroh.net/channel/fouroh-llc

> and I have a Gitea repository installed - all under YunoHost.
https://gitea.io/en-us/  Gitea is a community managed lightweight code
hosting solution written in Go. It is published under the MIT license.

> I am going to be publishing all I print (dimension, material, etc.)
> OpenSCAD scripts, PNG images, printable models (STEP) and maybe even
> animation - OpenSCAD has some basic but functional animation capacity.
>
> I stopped subscribing to the git mailing list
It can be busy with developer discussions. Its archive is at
https://lore.kernel.org/git/ There's a Git user list at
https://groups.google.com/g/git-users/ but again is more git usage
focussed, rather than 3d model version control, so may not have any answers.

> as I do not want to pollute with newbie questions, but your answer is
> really valuable to me  because now I have some idea about how a pro
> would go about this.
One useful example for software version control is
https://nvie.com/posts/a-successful-git-branching-model/ (also web
search for critical reviews of the approach).

Key is to be clear about the design artefacts you need to store as
revisions, and what to do about 'compile' artefacts.

Ask questions about revisioning on all the CAD sites, both open & paid
CAD to get insights. A key one to ask is about the "diff" mechanism (if
available) for OpenSCAD - maybe they could have an indicator that shows
how much deviation from the last revision you've made (i.e. how easy to
create a 'diff') so that once you go past 100% you can commit a WIP at
the last undo point (I guess there is at least a 1-step undo, so you can
have a diff report)

> Gitea it is, thanks!
That at least lets you have your own local store while the design IP is
under quarantine.

--
Philip
>
> On 2021-01-11 12:28, Philip Oakley wrote:
>> Hi Sandor
>>
>> I haven't used OpenSCAD but I thought it worth mentioning some personal
>> points about using Git for Engineering products, where variants
>> proliferate and build-products must be  versioned.
>>  I had a go with FreeCAD a few years ago to create an insulating spacer
>> that the mech eng had forgotten...
>>
>> On 05/01/2021 09:57, Mr. Sandor Kunyik wrote:
>>> Greetings,
>>>
>>> If you were to design a new workflow, what key observations would you
>>> make in regards to OpenSCAD scripts?
>>
>> I'm sure that git is able to store and version all the scripts and
>> products, but it does need a vision about how to present the
>> organisation of the scripts and products, especially for engineered
>> items. Remember that software version control is just drawing office
>> procedure with the hard stuff ripped out ;-) [1]
>>>
>>> As a quick illustration: I have a model with cavities to hold hex
>>> bolts and nuts. I fine-tuned the model to print on PrinterA, using
>>> FilamentA, SettingsA.
>>
>> Is the fine tuning done via the scripts, or is it manual. If it is the
>> latter then it will need the user to record in the commit message for
>> the revision the various what/why/how aspects that aren't obvious from
>> the 'diff'. Does OpenSCAD have an informative 'diff' capability? If it
>> is just a 'compile for printerA using known-tool' then it could be an
>> automated commit message as you are storing a build product (If it was
>> regular software it's likely it's a binary..)
>>
>>> Once in "production" I need to "freeze" all relevant scripts,
>>> especially when using multi-file structure. If the modules receive
>>> parameters I need to "remember" those parameters (such as the radius
>>> for the hex, and the dept of the cavity), and if they use hard-coded
>>> values I must remember not to change them. Otherwise I cannot
>>> repeatedly print the same model.
>>
>> So these parameters are essentially a 'configuration file' (inc. the
>> hard coded values). If you auto generate such a file then it can easily
>> be stored within revision (commit) - It is important that the scripts
>> should be able to work directly from that config file (idempotent [2])
>>
>>>
>>> Now imagine this for the entire standard set of hex bolts - each of
>>> these were fine-tuned, test-printed and verified.
>> A library? Hence a sub-module perhaps. 
>>> The rationale behind this to guarantee that the models trying to
>>> conform to a standard (such as ASME B18.3) stay put, while models
>>> receiving non-standardized sizes such as Nylon 6/6/ (which have bigger
>>> hex heads) stay separated, and tweaked to work with each supplier.
>> A configurable library item? Tricky. I remember a project that need to
>> change 20,000 drawing because they changed the paint colour (green to
>> grey), and then the next major order was in the old colour! In software
>> terms its like 're-skinning' a GUI, but worse.
>> More likely you'll have a separate sub-module-library for these
>> 'specials' where the source part is cherry-picked (give give a backward
>> textual reference) and then modified locally giving git level
>> traceability. 
>>>
>>> My question is, should I just "hardcode" everything, set up forks or
>>> branches for all past scenarios? So far I only have a few dozen models
>>> and I'm already having a hard time finding models I printed and used
>>> in the past, to print again. How do I structure all this?
>>
>> The hard part is to be both the 'design authority' that signs off the
>> 'release' and also the day to day designer trying things where it's a
>> 'fingers crossed' hope that this 3d print run will actually produce what
>> you want and expect, but mainly it's a case of realising the mistake and
>> cycle it around.
>> You should at least use tags for the good release commits, to make them
>> easy to find.
>>>
>>> I am a mechanical engineer not a coder, new to all these.
>> I feel you pain. Some of the above may be more suited for those who
>> actually design and contribute OpenSCAD, rather that a user getting
>> started.
>>> Maybe git or revision control is not the correct tool for this job?
>>>
>> As an ME you will know that without [good] revision control the world
>> falls apart for anything other than bespoke item home jobs!
>>
>> Git is great because it give you full control, and local storage,
>> without taking up too much room.
>> Git is a problem because it gives you too much control and too much
>> choice. Start simple, be open to the 'mind-shift'.
>>
>> Add any (i.e. more) files that you use to Git. Remove them (one at a
>> time) when you stop using them. They will still be in the history!
>>
>> Commit often: including halfway through a change - you know you will add
>> more and then more, then more tweaks before you print - have a commit
>> for each. I.e. distinguish between 'Printing' runs, and the act of
>> 'visualising the part' in the OpenSCAD viewer - both steps get a commit,
>> with concise description. (probably every 5 minutes or less!)
>>
>> Use the 'git gui' and 'gitk' to visualise how you have developed and
>> progressed. (or a GUI of your choice -> CAD people are NOT terminal
>> people!!)
>>
>> Git unfortunately lacks a short command to allow you to park a completed
>> items onto a 'Completed' branch that's just an easy quick way of seeing
>> those finished items (Git has the view that they [old software versions]
>> are 'gone/left behind', with just a few v# tags), so I don't have any
>> great solution for that.
>> If you have concise commit subject titles and messages, then it's easier
>> to search history for "print: insulating spacer widget v2.1" (and before
>> that "visualise: insulating spacer widget v2.1a", 1b, 1c, 1d, 1e...).
>> You may want to allow-empty commits for ease of recording!
>>
>> Hope that helps.
>>
>> [1] Drawing Office procedures allow for non perfect machining, serial
>> numbering, etc. Software generally asserts perfect replication,
>> repeatability and machining.
>> [2] https://en.wikipedia.org/wiki/Idempotence
>> [3] concise: adjective - giving a lot of information clearly and in a
>> few words; brief but comprehensive. "a concise account of the country's
>> history" (Git: without repeating the obvious changes shown in the diff!)
>