There's a noesis script for "To LOVE-Ru Darkness: Gravure Chances" that also tackled .BUM files, but it doesn't seem to work with this game. I've attached the script and sample files from this game. Any help is much appreciated. There's also the Steam PC port if anyone wants to research that, but there's no script that I know of that properly decompresses the game's main .DAT file. The .BUM file type was also apparently used for Senran Kagura: New Link, a game that, like Uppers, happens to be a Marvelous-owned IP. So maybe there's some connection there.

Uppers Sample.zip

Edited July 22, 2025Jul 22 by OugiSHU

From a quick glance (sub meshes need to be assembled):

edit:

Quote

There's a noesis script for "To LOVE-Ru Darkness: Gravure Chances" that also tackled .BUM files, but it doesn't seem to work with this game.

On my side the script works partially, "Detected file type: To LOVE-Ru Darkness: Gravure Chances
datasize:  0x7a228"

fails with index error then after bone names. Might be fixable.

edit 2: the skeleton was created, at least. xml version, see zip

bones.zip

Edited July 22, 2025Jul 22 by shak-otay

7 hours ago, shak-otay said:

On my side the script works partially, "Detected file type: To LOVE-Ru Darkness: Gravure Chances

datasize:  0x7a228"

fails with index error then after bone names. Might be fixable.

The script works better now. Strangely it's the "Senran Kagura" one. (Need to check the differences...)

Edited July 22, 2025Jul 22 by shak-otay

Thank you for looking into this. So an existing Senran Kagura script was able to read these models in the end? Can I ask for an upload of the modified script to try it out? I want to see also if Noesis exports without breaking the UVs.

The change in the fmt_sknl_bum.py in your uploaded zip is simple but it probably breaks the parenting. Don't have the time to check this.

So use on your own risk, simply comment out like so:

            #else:
            #    matrix[3] = eval(slide.parentNode.getAttribute("TRNS"))

 

You were right. The weighting breaks, and there aren't any UVs. The mesh and bone positions are correctly exported, though. I tried on both NPC models and playable models. 

There are uvs, but they're wrong, so not visible.

The rapi "uv line" (for FVF size/stride 36) needs to be patched like so:

				rapi.rpgBindUV1BufferOfs(ARAY[DRWA[a][0][1]][2], noesis.RPGEODATA_HALFFLOAT, ARAY[DRWA[a][0][1]][1], 20)

Strangely the uvs are not visible with .dae export, so I tried wavefront obj:

Edited July 24, 2025Jul 24 by shak-otay

That worked! UVs show up and work perfectly with an FBX export too! Applying textures to this test model, she looks metallic skinwise in Blender, but I'm guessing that's to do with the game's toon shader (or I'm in need of another texture). I also tried on a playable character, and it worked perfectly! All that's still busted is the weighting of the rig, but I'm thankful with this much all the same! Thank you kindly! Can I tip you for your help at all?

55 minutes ago, OugiSHU said:

Thank you kindly! Can I tip you for your help at all?

The usual tipping currency here is thanks and likes.

Will keep that in mind! Cheers!