[Patentpractice] FreeCAD and Inkscape for patent drawings, hatching versus shading, and OS questions

[Timothy Snowden]

Oh, and if you're used to Visio, don't ignore LibreOffice Draw. It takes 
a bit to understand the LibreOffice way of doing things, but Draw is 
actually a pretty decent Visio replacement.

On 10/22/2025 8:51 AM, Timothy Snowden wrote:
>
> BTW - if you want a complete MS365 replacement, check out Nextcloud. 
> It's not perfect, but it's actually pretty good, and you can run it 
> entirely on your own hardware if you want, or you can pay a service 
> like https://www.federated.computer/ to manage it for you (they are 
> good to work with) -- and they use Jitsi (another FOSS project) for 
> videoconferencing (been one of the most reliable videoconferencing 
> services I've used).
>
> On 10/22/2025 8:49 AM, Timothy Snowden wrote:
>>
>> I've used all three. They work, and are great. I still use Inkscape 
>> on at least every other application (I don't use Visio, but I do use 
>> WithEdge for drafting -- hence my less reliance on flowcharting). I 
>> use FreeCAD semi-regularly to open a STP file and generate SVGs to 
>> take to Inkscape and modify. DrawIO is also a good project for 
>> flowcharts (free, but not fully open source) because Inkscape is not 
>> the greatest / most efficient with flowcharts. yEd is also a good 
>> graph editor (again, free but not open source) and runs on Ubuntu 
>> last time I looked.
>>
>> 1. Inkscape - I created a template with different common drawings I 
>> commonly use. If I'm preparing a complete drawing set in Inkscape, I 
>> really like Inkscape's ability to look at all the pages like a 
>> 'canvas' instead of one at a time. I also use snapping heavily. So I 
>> guess that answers your questions -- I build out the drawing pages 
>> directly on Inkscape. I've thought that Inkscape's extensability 
>> would open the door to a really nice patent drawing specific plugin 
>> for automatic numbering, generating a reference list, etc. ... but 
>> never had time to pursue that.
>>
>> 2 & 3. I've run both on Ubuntu. For a few years I ran only on Ubuntu 
>> for all patent drafting. FreeCAD & Inkscape both run well on Ubuntu 
>> -- possibly better than on Windows. No particular advice -- they 
>> pretty much install natively. If you plan to modify them you might 
>> want to avoid snaps, as those aren't as friendly to modification.
>>
>> 4. Not FOSS, but I use PDFX-Change to rasterize everything to B&W 
>> anyway - I forget the exact algorithm but it does a pretty good job 
>> of getting shading as close visually as you're going to get in B&W 
>> only. Probably my primary pain point on Ubuntu is the lack of really 
>> good PDF software. Good CAD software used to be the other lack 
>> (VariCAD was your primary paid option), but FreeCAD is plenty capable 
>> now.
>>
>> 5. For shading, I typically try to use a cross-hatching pattern fill 
>> in Inkscape and avoid 'shading' per se. However, if you're coming 
>> from FreeCAD, you can cross-hatch a cross-section (by default), and 
>> change green to B&W, and it comes out pretty good.
>>
>> 6. Not sure -- I would imagine so, but I'm not clear exactly what 
>> you're doing in shading, so there may be several tools that could do it.
>>
>> 7. Theoretically, yes.
>>
>> 8. Well, no, since we can't see the source and AFAIK PatentCenter 
>> doesn't publicly adhere to a given color standard, I guess we can't 
>> know that PatentCenter will reliably properly interpret those, but 
>> that would equally affect all other files too, since that's how 
>> everybody else is defining the colors too. So ... I think that it's 
>> safe to rely on from a practical point of view.
>>
>> Hope that helps.
>>
>> On 10/22/2025 8:30 AM, Rick Neifeld via Patentpractice wrote:
>>> *Background and Questions:*
>>> Being able to prepare complicated patent drawings has been on my 
>>> professional bucket list for a couple decades. To do so with purely 
>>> open source software is kinda on that list.
>>>
>>> I can now design 3D models, generate 2D engineering drawings 
>>> therefrom, and export the drawings to SVG, from FreeCAD. And I can 
>>> use Inkscape to import the SVG files and readily mark them up with 
>>> sheet numbers, Figure numbers, reference characters, curved and 
>>> straight lead lines, arrows, and feature numbers, and then export 
>>> them from Inkscape to pdf (or to a bit mapped image format 
>>> suitable for including in a strict DOCX file).  And both FreeCAD and 
>>> Inkscape are free and open source.
>>>
>>> 1. Has anyone else gone down this path and have any observations, 
>>> dos and don'ts, or the like? Did you use all ten default (or 
>>> multiple) views in a page or stick to one view? Why or why not?
>>>
>>> *Ubuntu Compatibility*
>>> I am currently using FreeCAD and Inkscape on Windows 10.  Upon 
>>> review of Windows 11, it seems to me a bridge too far.  Windows 11 
>>> locks the user in to Windows and MS products for all eternity. The 
>>> combination of a TPM 2.0 chip required by Windows 11, mandatory 
>>> secure boot, and automatic turnon of bitlocker on boot, tied to the 
>>> users microsoft ID, does that.  Ubuntu, FreeCAD, and Inkscape are 
>>> all free an open source.  And I have enough technical oomph to load 
>>> and use ubuntu on some computers. So I plan to do that, keeping my 
>>> existing Windows boxes, but moving to all free and open source.
>>>
>>> 2.  Has anyone run FreeCAD on Ubuntu? Got any sage or stupid 
>>> advice?  Any difference from running on Windows?
>>> 3.   Has anyone run Inkscape on Ubuntu?  Got any sage or stupid 
>>> advice? Any difference from running on Windows?
>>>
>>>
>>> *Hatching versus shading*
>>> Hatching, what the patent rules identify as oblique lines to 
>>> identify cross-sections.
>>> Shading, what the patent rules identify has usable to identify 
>>> curved surfaces and, in perspective view, flat surfaces
>>>
>>> 4. My issue here is the PTO conversion of image data to bitonal, at 
>>> least for pdf images.  First, I am guessing that bit mapped objects 
>>> in "DOCX" files are likewise converted to bitonal.  Does anyone know 
>>> if that is the case?
>>>
>>> 5. Assuming PatentCenter converts to bitonal an uploaded grayscale 
>>> pdf image file, how does it handle "shading."  Shading seems to be 
>>> ambiguous because it defines what we see and not the data format. 
>>> For example, I could make something look shaded rendaring a a 
>>> bitonal image file in which every third pixel was black, the rest 
>>> white.  But that is not generally how its done, right?
>>>
>>> 6. Is there some method of defining in Inkscape (or some other svg 
>>> file editor) shading in bitonal data format?
>>> 7. Can I define the line spacing and dimension small enough in 
>>> Inkscape so that the result appears to be shading instead of 
>>> individual lines?  If so, what settings?
>>> 8. FreeCAD and Inkscape allow for RGB or RGBa settings that are 
>>> equivalent to white, and black. For example, 255,255,255 and 0,0,0.  
>>> Do we know that PatentCenter will interpret those as the proper 
>>> bitonal values, aka white and black?
>>>
>>>
>>>
>>>
>>> Best regards
>>> Rick Neifeld, J.D., Ph.D.
>>> Neifeld IP Law PLLC
>>> 9112 Shearman Street, Fairfax VA 22032
>>> Mobile: 7034470727
>>> Email: RichardNeifeld at gmail.com;
>>>
>>>
>>>
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