Hello!

I would swear that in the past I was able to open the OBJD of an object, go to Materials where the presets are and export the XML of a certain preset by clicking an arrow... then editing that XML with a text editor and importing it back to the aforementioned OBJD. I cannot do it anymore. When I click the arrow it just opens a window listing the resources (TGI) referenced but nothing about exporting or opening the preset XML. I mean in S3PE. Is it something about my settigns?

I believe S3PE can only do this for CASP resources- for objects, you'll have to use Texture Tweaker to access the internal XMLs.
Could also be that some objects support it and some don't.

Oh, shoot! It must have been that... I probably did it with a CASP I guess. I did managed to do what I wanted with Texture Tweaker... the problem is that when I do so, Texture Tweaker changes the order of all the lines that define the preset (like the order of referencing the overlay or the stencils) and I would like to be able in the future to compare the original object and my default replacement and see clearly what I tweaked. For example of I just disable one stencil I can copy in my comparing software the OBJD of the original object and my replacement and the program highlights the one line where I clicked "False" for that stencil. But if I implement the changes (in this case change of patterns) using Texture Tweaker, because it alters the order of many things, it seems like I changed practically everything and I cannot spot clearly (I won't in the future) the actual change. That is why I have an interest in modifying the XML directly.

Ah right, a lot of tools write the XMLs in their own format (CTU does it as well). A quirk of coding a program that writes a file instead of just exporting it, I suppose.

One workaround to have an unmodified copy would be to make some kind of non-edit to the object (change a colour to the exact colour it already was, for example) and save that. Then make your real changes, and save that as a copy.

Thank you for the input, although I am not sure I fully understand the suggestion for a workaround.

The idea is to prompt Texture Tweaker to write a new XML that otherwise has all of the same information as the vanilla / EA one did, just in that new format. That way, you should be able to compare it to your edits.
That should technically work as long as the order it outputs the lines is the same every time.