https://sims4studio.com/thread/9464/tutorial-correctly-make-lods

This tutorial is going to be how to make LODs correctly without having all those weird spaces around the sim's joints . Like this...

First thing you do is export your LOD1,2,and 3. I saved mine as their original name.

Go to your original mesh .blend file and extract only your mesh. Do so by 1) going to edit mode then 2) selecting all your mesh by pressing A.

Then go to the "uv image editor and 3) select the button with a cursor and colon on it. Your mesh will be selected. 4) Just press A to deselect everything.

I just press B and select only my mesh and as you can see, it is also selected in the 3D window.

Press P and click on selection and this will separate your selection from the rest of the mesh.

Now delete the rest of the body except for your mesh. It will look like this...

Go ahead and save your .blend file. DON'T OVERWRITE YOUR ORIGINAL . SAVE IT UNDER A DIFFERENT NAME. I saved mine as "single.blend"

. Open your LOD1 and append your mesh by going to "name of your mesh file"> Object> Studio mesh....

Make sure your scene panel looks similar to this and delete whatever else is there.