I've posted some information about the kit design process. As 3d printing has become more mainstream, more model railroaders discovering the endless potential that it has for their hobby.
John Crowdis has a great YouTube channel called JC's Riptrack where he covers many different model railroading topics. Several months ago, he posted this great video that explains the process involved with designing and printing an n scale beehive sawdust burner. It does a good job of summarizing the steps involved.
Check it out: https://www.youtube.com/watch?v=icZv09H2em0