I worked on a similar feature and used the Render Target solution aswell, the important thing is that you adjust your lightning properly to prevent the background color from creating a border around your 3D model. The tutorial you linked seems to be slightly outdated, but you probaly already noticed that. The material you create from the render target, will need to have it’s Material Domain set to User Interface and Blend Mode set to Translucent. Other than that the tutorial seems to cover most of it pretty well.