I need some help, nothing I've tried seems to work.
First I tried exporting from 3ds Max (the source files are .max), I tried dragging the .dae file exported from 3ds Max to the online glTF converter. It gives me a resulting .glTF file that is 1kb and has no mesh data.
2nd I tried exporting to collada with Blender. Unfortunately Blender seems to drop my textures, but dragging the .dae to the online glTF converter resulted in what appeared to be a valid glTF file (without textures). The model even showed up in the little window. However, when I tried to load the model into my cesium app I get an error saying "RangeError: Invalid array length".
3rd I tried exporting as collada with Open 3D Model Viewer (Uses Open Asset Importer). From here I was able to export what seemed like a valid collada file with textures. I tried dragging it onto the glTF converter, it gave me what appeared to be a valid glTF file, but the model never showed up in the little preview window. When trying to load this glTF file I got the same error as above "RangeError: Invalid array length".
Unfortunately I can't send the models to anyone, but I've even tried just exporting a simple sphere from 3ds Max with the same result, the converter just barfs on the 3ds max exported collada files.
Anyone have any idea how to get these models converted?