Normally, the rule for questions that have overlapping scope like this situation is "if it's on topic, don't migrate it". For instance, a question about Aruinos asked on Electrical Engineering would not get migrated to the Arduino site.
However, I don't feel the situation to be the same here. ~10% of all questions on EE.SE are tagged with arduino. ~0.1% of our questions are tagged with blender. 3D questions on our site always feel like orphan children to me. We've agreed to take them, but they can often contrast starkly with the rest of the questions on our site.
I'm fine with migrating blender questions away from our site and giving them a better home. I discussed this with iKlsR (one of Blender's mods) who is okay with us doing so for quality questions.
If this is the consensus, then the proper way to handle them is to flag as "other (needs ♦ moderator attention)" and just make a note that you think it should be migrated to Blender.SE. I'll pop into the chat room and confirm with any active Blender members that it's a decent question worthy of migrating.
This would be for new questions only. Don't flag the existing 10 or so questions that we have tagged blender, we won't (and sometimes can't) migrate ancient questions.