How to join segments of a low-poly character into one mesh without losing rigging?

Question

Apologies for my lack of correct vocab, I'm very new to Blender so I don't have the correct words for things just yet.

I have been in the process of making a version of a low-poly character for some time now (adding an extra hip part to them to allow me to use them in Unity) and I have managed to do everything I need to do so far. But, to get something into Unity I have to export my character as one model instead of as the segments I currently have my character split into (this is also to be able to combine all of the materials that my model has into one, as Unity requires that I do so).

I first tried joining all of the segments into one mesh (Ctrl + J) but that meant that the armature was no longer able to control the segments, which isn't what I want.

Before joining, I'm able to pose the model however much I want.

After joining, the bones won't move the segments anymore.

What I want to be able to do is to join all of the segments into one model, whilst also being able to control the seperate parts as I would be able to do before joining.

For reference, the method I used to parent the bones to the segments is explained here (specifically the add-on 'Parent to nearest bone')

https://www.youtube.com/watch?v=DDeB4tDVCGY (5:43)

Help would be much appreciated as searching around didn't tell me what I needed to know and since I have little experience with Blender, I wasn't able to understand any answers that I did manage to find on this topic.

Thank you!

Answer 1

You have parented all the limbs with a simple parentage mode, not the Armature Deform mode, it means that for the moment each piece is parented to each bone with a classical child/parent parentage, no Armature modifier has been created for the pieces, no vertex group has been assigned to them. If you're glad with the current rigging, you can keep it as it is.

If for some reason you need to join all the pieces together, what you can do is join the pieces with a CtrlJ then parent to the armature with the Armature Deform / With Empty Groups option. This option gives an Armature modifier to the object, it also creates a series of vertex groups that have the same names as the bones, but no vertex of the mesh is assigned to any of these vertex groups for the moment, you're going to do it manually. If you parented with the Armature Deform / With Automatic Weights it would automatically assign the vertices to the vertex groups, which is OK for a flexible rigging, which is probably not what you want to do right now, it looks like you want each bone to influence each part, and not bend any other part.

Once parented with the Armature Deform / With Empty Groups option, select each part and assign it to the correct vertex group (the one that has the same name as the bone that is supposed to move it):