GPLv3 explained

GPLv3.md

GPL3 LICENSE SYNOPSIS

TL;DR* Here's what the license entails:

1. Anyone can copy, modify and distribute this software.
2. You have to include the license and copyright notice with each and every distribution.
3. You can use this software privately.
4. You can use this software for commercial purposes.
5. If you dare build your business solely from this code, you risk open-sourcing the whole code base.
6. If you modify it, you have to indicate changes made to the code.
7. Any modifications of this code base MUST be distributed with the same license, GPLv3.
8. This software is provided without warranty.
9. The software author or license can not be held liable for any damages inflicted by the software.

More information on about the LICENSE can be found here

If a company develops a 3D printer that uses Open Source software (under the GPL3 license), such as the Merlin code that's used with many commercial 3D printers, and the 3D printer hardware includes a patented addition that provides some unique feature, with modifications to the Merlin code handling the processing of that patented unique piece of hardware, I understand that the modified Merlin code needs to be made available as Open Source code, but does that have any impact on the patent that covers the unique hardware? Can the company still enforce its patent rights and prohibit other companies from building a similar printer that includes the patented part?

Looking at the messages just now...

@pedro15 If your android app is for private (?!) use, you are not distributing. If you pu it in the Google Play store (for instance), you are distributing. One of tackling this situation is to force the user to install the plugin after the instalation. Then you are not distributing anything and what the user does is none of your concern.

@RogerInHawaii In your case, it is important to know what you are patenting. Is it the unique hardware part? Even if you open source your software, your patent would protect the hardware design. As for the software side, any unique addition that you offer with OSS GPV3.0 must be open source. Patenting that part is difficult and even if you do, enforcing or protecting it would be difficult.

Disclaimer: I am not a legal expert, get advice from an IP lawer.

@hoang-innomizetech

All code linked with GPL 3.0 source code must be disclosed under a GPL 3.0 compatible license.

There's is no such text on the linked page, where did you see it?

Hi,
You mentioned about open sourcing the source code. Well, does that mean I need to open source my entire application or only the modifications I made?
Thanks!

@shubhh123 , My reading of the GPL3 LICENSE is that you only need to open source YOUR VERSION of the open source code that you use in the application, including any modifications you made to IT. Your program may well include other code that you developed and even code that invokes part or all of the open source code you included (and potentially modified), but you do NOT have to make that other code open source. So, no, NOT the entire application, ONY the open source code that you included in the application (plus the modifications you made to IT).

Disclaimer: I am not a patent attorney.

Yet another question: (Trying to protect my own software from being open source).

Suppose I set up a secondary processor, like an Arduino, and have some of MY software running on it. I have the open source code running on the primary processor and modifications I made to that open source code SENDS INSTRUCTIONS, perhaps by way of serial communications, to the secondary processor to have that secondary processor run its own software (that I wrote).

Is the software that I'm running on the secondary processor considered to be "part" of the open source code and therefore must also be made open source? Or can I (potentially) patent or copyright or otherwise protect that software I wrote that's running on the secondary processor?

Thanks man, I was a bit overwhelmed by the unholy amount of stuff it said, and now I actually understand it.