WARR, students from TU Munich have been hard at work continuing their hybrid propulsion work and experimentation. With the latest fuel grain being assisted by 3D printing the shape and then pouring the HTPB in, thus avoiding any demolding issues that may arise as it is all burnt as one.
I know RML Spacelab have used this technique, taking it as far as getting individuals at home with a 3D printer to print and send in the mold parts required. A great way to contribute to a project.
I look forward to seeing this engine fire, it should be spectacular!