I'm trying to get the 3DViewer to show OBJ-files. I'm not quite familiar with 3D rendering and the different formats, but the documentation of the 3DViewer says it supports OBJ files. I have created an app with the viewer, all according to the learning path. When uploading and opening the sample jt-files, everything is working fine. Now, I have a zipfile containing a .obj file, a .mtl file and some png files. If I upload the obj file, it goes to 100%. And when I try to open the model, nothing shows - the viewer stays gray. If I try to upload the zipfile, I need to enter some "Entry path" (default value: the name of the zipfile), but then uploading gives an error: "java.util.zip.ZipException: invalid entry size (expected 0 but got 366997 bytes)" Any advice?