Kelleytoons (9/24/2020)
No, you cannot do this.
The best you can do is export a CC3 base mesh into Blender and modify it there, but you can NOT add or subtract any vertices nor can you change the order of them (this last isn't normally an issue, though -- but do NOT add/subtract any). The results CAN be imported back into CC3 as a morph.
thanks for the answer, but how can i modify it without modifying the vertices? like what if i wanted to sculpt or something?
also after editing, does it still counts as CC3 base mesh or can i treat it as my own?