Yeah, there's no professional 3D modeling software on mobile as far as I know. I had to use a computer to make somewhat decent 3D models, which kinda defeats the purpose of hyperPad of making it as easy as possible to make games.
July 7th we will be doing a livestream with a teacher, Steve Iliano, who will be training teachers on how to teach kids how to use hyperPad. Maybe you would be interested in joining? I will be posting more information to sign up for it this week !