In the latest development release of ModelConverterX a new feature has been added to the hierarchy editor. You can now also modify the material of model parts in the hierarchy editor. When you click on the material name you get a list of all materials in the model and can select which one should be applied to the part. If you hold down the control key while selecting a copy of the selected material is made, so that you can change attributes without affecting other parts that use the same material. The video tutorial below shows this new functionality.