You could send the 3d object encrypted, and then decrypt it on the front end in some minified code and provide some confusing method to pass the decryption key. With enough redirection and slicing things it could make it difficult for an adversary to obtain it. You could also send it over in a non-standard format, or as you suggested, chunking the file to be reassembled on the frontend.
None of these would be perfect, but would significantly reduce the number of people capable of cracking it and make it so the effort isn't worth the result. Most people's 3d models are not worth the effort to steal when there is a mountain of free ones available, and even if they get away with it, selling or using the model would violate copyright.
So, if you would like to keep some security, follow any of the steps that are easy enough to implement in your workflow, and know the risks of your assets being taken. Even compiled games from major studios have their assessed copied out of their games (and amusingly sometimes replaced). Once something is on someone's computer, and it is something their computer has to represent to them, there will usually be a way of prying it out of there if someone is tenacious and skilled enough.