Thanks!
I noticed that Assimp 4.1 with GeeXLab I did not see textures for x3d. I built assimp_viewer for Windows v5 rc1 and textures are displayed for x3d. I could export to gltf (and others) and then load normally with GeeXLab.
I did not test assimp_viewer with Assimp 4.1.