If you can export an hf2 file format then saving up to 2Kx2K hf2 file as height.hf2 and run my little dragon flight app in the same dir would give you that simple 3D viewer. Its what I wanted too so I wrote that.
ViewingDale - getting browser details...

If you cant export an hf2 from wilbur then save an 8bit greyscale png file or bmp file as height.png / height.bmp and it should also work. It will do 16 bit heights if you can obtain the LSB 8 bits as another greyscale as height_minor.png. Also, if you put in a color.png . color.bmp then it will colour the terrain as well. Otherwise it has just movement keys, raise lower landscape and some screen save etc but thats about it.