Sorry for not replying sooner, I was on holiday. But then again, I don't have much to add to what AeroShark333 already said. It highly depends on your application how to obtain the point in 3D.

Ok, but how does the rest look like? Blank? Textured with that one texture? Not present at all? A screen shot might be really helpful.

I had brief try on loading (but not rendering) the object and I can't see anything wrong with it. This is an excerpt  from the log output:

2022-06-07 16:56:12.146 6204-6234/com.example.androidtestcase I/jPCT-AE: Text file from InputStream loaded...2796 bytes
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material FrontColor!
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Color_E04!
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Color_E03!
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Color_007!
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Carpet_Loop_Pattern!
2022-06-07 16:56:12.147 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material _Wood__Floor_2!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Stone_Pavers_Flagstone_Gray!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Texture named 02/Stone_Pavers_Flagstone_Gray.jpg added to TextureManager!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Wood__Floor!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Texture named 02/Wood__Floor.jpg added to TextureManager!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Stone_Coursed_Rough!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Texture named 02/Stone_Coursed_Rough.jpg added to TextureManager!
2022-06-07 16:56:12.148 6204-6234/com.example.androidtestcase I/jPCT-AE: Processing new material Groundcover_RiverRock_4inch!

Prior to loading the model, I assigned two textures to the manager:

TextureManager.getInstance().addTexture("02/Carpet_Loop_Pattern.jpg", texture);
TextureManager.getInstance().addTexture("02/_Wood__Floor_2.jpg", texture2);

Note that these textures don't show up in the log, only the ones that have no matching names in the TextureManager do. As all working as expected.

I'm not sure, what your actual issue is...you loaded the textures and the model but the textures don't show on the model? If that's the case, maybe you can post a screen shot of how the model looks instead?

Are these materials really used in the obj file? Maybe the export went wrong?

It should work that way. Have a look at the log output when loading the file. You should get log messages if a texture name can't be found and you should be able to see what exactly these names are.

After playing some racing games on my old computers (Amiga, C64...), I felt the urge to try something like that for myself on a more modern platform but with a retro look. I wanted to code something that at least generates a road and moves a car. I'm not sure, if this is going anywhere...if it is, it'll be some Android game...but I'm still undecided, if I really want to do that.

Anyway, it's basically code that generates road tiles based on an RNG and then warps, rotates and translates them to form a continuous road. The tiles get enabled/disabled based on the player's position, so that in total, not more than 30 tiles are being processed for each frame. So even if it looks like a single 3d mesh, it actually isn't.

Then it places a car sprite (ripped from Outrun), plays some music (also ripped from Outrun...) and moves along.

Here's a video (with german descriptions, but anyway): https://youtu.be/tAsdOGt0i28

Edit: It's using the software renderer for now, hence the shimmering.

I am against war!!!

Who isn't? Well, expect for a few idiots, I suppose. I don't I see the point in the current "distancing game" from everything russian just because the russian leader does crazy things causing tremendous suffering for no good reason. My neighbors are from russia. What am I supposed to do now? Not like them anymore? They haven't changed, only the world around us has...sadly.
Just recently, I've read my grandfather's war diary from WW2. He was in ukraine and russia trying (more or less fruitless) to conquer oil wells for nazi germany. He didn't want to be there, he was a teacher...Hitler wanted him to be there.
This isn't a politcal forum, it's all about 3D, software and basically having fun with that stuff. Everybody is welcome here. Well, except for these chinese guys who constantly are trying to post links to escort services.
Let's hope that there will be an end to all of this more sooner than later.

Is https://www.jpct.net/jpct-ae/doc/com/threed/jpct/World.html#setDefaultThread-java.lang.Thread- useful in some scenarios?

Not very likely. jPCT-AE sets is automatically to the main thread (i.e. the thread that created the world instance). If it's set to the wrong thread, all that happens is that more garbage objects will be created. There's no performance benefit in setting it to some other thread except if that thread is the actual thread that does the calculations.