Hi !
A) Get the source files :
1) you ask for permission from the original author if he/she is willing to provide you the source files and an agreement on what you can and cannot do
2) it is assumed you know how to adapt the design in order to be able to export to XP11, there are topics here and on the internet for that
3) When you release the conversion, you provide the terms of the agreement and credit the original author(s)
B) You don't have the source files :
1) you ask for permission from the original author if he/she is granting the permission to proceed on the conversion, and an agreement on what you can and cannot do
2) you post a topic (here for instance) and you explain the terms of the agreement
3) if someone who have the knowledge (I don't fully understand the process) and the tools (some of them are no longer available) is hiped by the objective (it's not always the case), he/she would help, providing the agreement is okay and the original author is always aware on time of what is currently done to/with his/her work.
4) Upon release, you provide the terms of the agreement and credit the original author(s).
5) If everything goes according to our philosophy in the communitiy (from as early as 1990 to this day) of contributors, especially on the fair use aspect (which have experienced many changes over the years, this, to protect the future of our hobby), you may benefit by learning the process of conversion, and even understand there are still a couple ways to achieve it). BTW, this can be discussed, and occur while in the process of converting.
C) You don't have permission/the original author doesn't answer.
1) You pick another aircraft from another creator and do A) or B)
2) If no option left, well, you're out of luck, like maybe create an entire aircraft from scratch... (this, if you want to remain on the "bright side").
D) You may find a way to reunite/retrieve/reassemble the set of tools to be able to do the conversion on your own. After all, it's all about files... Noone can prevent you from doing this, and personnaly, I think it's irrelevant as long as you don't release anything, not even your buddy who asks you "give it to me ! give it to me tooooo !".
What usually happens is you give it to someone, and he posts screenshots on Facebook and other people starts to ask for it, or, you decide to release the thing for XPlane without the consent of the original author yourself. That's the dark side. What's the problem one would say if it's free. Well, one hundred reasons.. Here are a few :
- XPlane and (MS)FS has some "features mismatches", when a creator makes a content, he does it with passion and overcomes the platform limitation by finding workarounds. If you are only doing a straightforward port, there are always things that won't work. Basically, you render meaningless the hundreds if not thousand of work by the original author.
- Releases of the kind often fail to credit the original author. Basically, people believe you made the thing, not the original author. That has a name : theft.
- Even if you credit the original author, how about everyone taking others work and make changes without permission, even if it's free ? Sounds great... until you start to become an actual creator yourself, you understand creating is not as easy as you thought, you must sacrifice part of your life (family, work, responsibilities..) to come up with something incredible. Despite being free, the value of the sacrifices involved translates into ownership, license and control over the creation. That's what credit and copyright mean : there is someone who worked hard to create this : that thing has a value, you just don't use it like if it was garbage.
(...)
- then, the original author gets demotivated, quit the hobby to concentrate on happinness (remember the sacrifices).. One disappointed creator, not a big deal ? Well, when I look of the thousands of topics asking if someone is willing to model this or that or if there is any particular project in the works, or how many airports are missing a decent to outstanding rendition.... well, maybe not loosing all those (freeware) creators along the years could have helped.
- some others have found an alternative : go full payware, make a solid licensing model through secured identification and payment, at least, if it's stolen on some obscure torrent in russian, I get a few bucks to buy me a beer, and let authorities handle the thing (not that I expect anything). Now you understand why we have less and less standalone installers anymore, you go through an identification platform first, so it is possible to track who leaked an illegally modified copyrighted material. As time goes by and network regulations gets more authority, we would be able to legally track those thieves and at least lock them out of the sector, eventually, even give him/her a hard life in the real world.
Note : we lose a chunck of freeware contributors each year for those reasons. Creators are not egoïsts monsters who are happy to only have a thing on MSFS and troll XPlane community (or the other way around). They are artists, and artists have an aspect of their personnality in common : a great sense of humanity. Just ask, if you get successfully in touch, you'll likely get permission. The exception I know of is the original author bound to some sort of exclusivity agreement with a brand or a platform. He/she would explain...
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This big blah blah is not a lecture. It's to educate/explain, could be innappropriate for some, or too long, on point for others, there is no universal way to explain something, I do put everything in one place to reduce misinterpretations (there will be misinterpretations).
I am not telling you are about to do something fishy, I'm not accusing you of anything. You asked for help in converting (MS)FS to XPlane, at this point, many of us have tried, I did, out of curiosity (but since I don't have XPlane...) It's only on your computer, it's fine. Noone knows about, it's fine.
I'm just answering the question, but due to the sensible aspect of the thing, some clarifications are mandatory : where's the written permission ? (It should be publicly written somewhere anyone can check for free)
The blah blah is the explanation why it matters, the permission being the condition before getting further. I don't expect anyone here to tell you on the fly the process despite many knowing it. Most people won't have the time to write all this, they will just not answer because they are also waiting for the agreement from the original author. Then, this is not the place to explain the process, the relucancy to share it is real as of today. That's not a question you ask for everyone to see (but it's okay to ask, just the answer addresses a concern you didn't expected). Now you know the way to go :
- you provide all the clarifications required on the situation
- someone willing to help contacts you
- you work with that person and the original author(s).
^^ That, at least is how it is for those who are here and related platforms. Elsewere, probably not.
Side note :
You said "DDS aircraft repaints to OBJ". I think you meant "PBR models to OBJ". "DDS" and "repaints" are misleading : to modify PBR textures only, ie the texture file (those who have depth and normal information) this is done in a raster graphic application such as Photoshop or similar. The model has to be designed to use PBR materials in the model file. Those are two separate part of the feature and are addressed separately.
Best regards.