3D models, no matter which 3D CAD program, are generally not easy to print 3D, if the design does not pay close attention to the subsequent production in the 3D printing process. Depending on the process and material, this requires certain wall thicknesses and above all flawless surfaces and transitions.
It usually takes several hours to prepare the 3D drawings in order to obtain a so-called “waterproof” (which is urgently needed in 3D printing). For this, too thin walls and overlapping surfaces have to be corrected, as well as wrong normals. The filling of cavities and holes takes a lot of time. And if the scaling factor of the 3D print model also deviates from the original data (for example, if the 3D model is originally several hundred meters long or long, but should be printed completely in a space of 15 * 15 * 15 centimeters 3D), is frustration even more preprogrammed, since the scaling down the entire game with the preparation starts from the beginning.
Conclusion: To make a 3D model 3D printable, you have to make it “waterproof”.