[SOLVED!] coordinate-handedness confusion

[KristyB]

I actually wanted to take a look at UE4 at some point, but I have zero experience with it at the moment

Maybe this weekend if there aren't too many hoops one must jump trough in order to download it.


I think the main problem is I assumed you imported the whole model as a single mesh, but it seems you are using loose bricks.

This means you need to convert the LDraw type 1 line matrices the same way the brick meshes did.

Not a lot of hoops to jump through if you're on Windows, you do need an Epic account though. Not sure about Mac, on Linux I had to compile it myself. Which wasn't terribly hoop-jumpy, I've seen worse with a lot smaller projects. HMU if you want help with any of it.

And yep, I'm aiming to build something that let's users drop an ldr file in their compiled game and have the engine read it on load to build a model out of it, hopefully to be released open-source as a tool for other game developers to use.

I'll walk through the z-flip of the type 1 lines here to make sure I am doing it right.
Flipping the z-axis for each set of coords in a line type 1: https://i.imgur.com/sBgsRFp.png
Results: https://i.imgur.com/l1p57El.png

Also flipping each axis of the rotator: https://i.imgur.com/ugFZC9t.png
Results: https://i.imgur.com/aH6oViE.png
Similar to just flipping the z-axis for each set of coords, but note the bricks on the bottom are more garbled.

Where did the brick meshes come from?

I downloaded lDraw's entire database, then import each .dat file using Toby Nelson's lDraw Importer: https://github.com/TobyLobster/ImportLDraw. I leave origins and orientations as-is. I then export as an fbx using the default transform settings, which are "-Z Forward, Y Up". This seems counterintuitive to me, but when I import them into UE4 (again using default import settings), they load visually being upright. For the project I am working on I will have to import and export every single brick anyways, so if there's transform settings here that you think would work better I could tinker with that.