yugutou When copying and pasting weights, the order in which vertices are selected is crucial; generally, weight information copied from a single vertex can only be pasted onto a single vertex. However, this allows copying and pasting weights across multiple vertices if the vertices are selected in exactly the same order.
While enabling copy-and-paste for multiple mesh attachments might be possible, it would require the user to exercise extreme caution to ensure that the vertex selection order is exactly the same. This would make it difficult to execute the operation successfully. Therefore, I believe that the Weld button is the easier option for aligning the weights of multiple mesh attachments.
As @CDO mentioned, you cannot copy a bone that is bound to a specific mesh and paste it onto multiple mesh attachments. This is only possible for a single mesh attachment.
However, if you first select multiple mesh attachments, then click the Bind button in the Weights view and select the bone, you can bind all those mesh attachments to the same bone at once. So, if that’s what you want to do, I recommend adjusting the order in which you perform the binding steps.
