New member and aspiring modder here!

For days now, I've been trying to learn modding (finally - took long enough). Everything has been going fine so far.. except for meshes. I just can't get Blender to work nicely with all the other programs I've downloaded. I'd love to try Milkshape in case it works better with importing/exporting, but I can't afford it just yet, and apparently the needed plugins don't work in the trial version. Unless that's no longer the case?

Anyway! I've been trying to debug my issues, so I tried something very simple. I made a fresh project in TSRW without any modifications and exported the mesh from it. I imported the mesh to Blender, again made no changes, and exported it right back out. I used MeshToolKit to convert it from wso to obj and back in between since I can't open wso files in Blender. I really made no changes in the mesh at any point, so it should still work, right? Except it doesn't. When I try to import the mesh back into the TSRW project, it gives me these different errors:

When importing the obj: "Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: Index"
When importing the wso: "Wrong number of groups, expected 2 found 1"

I've been googling so much about this, and these issues have been popping up for others as well, but I haven't yet found a solution that would've worked for me. I'm not sure when the files become unusable for TSRW either. Is it when I export them from Blender, or when I convert them with the ToolKit? Regardless, I understand there being issues with my modified meshes.. but this last test I really didn't modify in the slightest, simply exported and imported here and there.

Any help and nudges in the right direction are appreciated!

Normally when you have that, it means that the group name you are importing does not match the group names of the object you are replacing.

The second one refers to the number of the groups you are importing. The it says you are importing an object with one group name rather than with two group names. I believe that in the TSRW the group names for the object of the group 0 and group 1. When importing back into TSRW, you have to name the object groups in the same way so that the program recognizes it.

That's definitely where it borks up for me, then - though I have no idea why since I've never touched the groups and their names. I've only done modifications on the models, but everything else I've left be, just so I could avoid these kind of problems. So somewhere, something borks and I'm just not sure where and why. My biggest suspect is still when I export the mesh from Blender, but I'll need to test that more to be able to say for sure.

Does Milkshape have these kind of problems? Or is there a workaround for this in Blender? I have to admit, I am completely new to Blender, and I've tried to fight with the groups when trying to resolve this but nothing really seems to do anything. I used to use 3ds Max in uni, but that was years ago, I doubt I'd know how to use that anymore either. I'll try to get Milkshape as soon as possible, but for now, I'll have to try and make do.

TSRW files : C:\Program Files (x86)\The Sims Resource\TSR Workshop\Extras\Blender

Inside the blender folder should be two plug-ins that export. Wso files to blender. I have never used this before but you can Copy the two plug-ins into blender and see if it works.

Although I use blender, I also use milkshake as a bridge between my objects and TSRW. In the folder linked above is another for milkshape that let's you export and import. Wso formats into and from TSRW.