Replace textures using images / Everything is black

Issue is on IPAD/IPAD PRO. The texture is black on some material when it applied with Image. The Model is hosted on server. Not sure why shape spark have this issue. Can someone help ?

Looking at the link that you have sent us via email, some textures that the model uses do not have power of two dimensions which is a requirement for iOS devices. For example Charcoal-Gray_board2.jpg is 1000x1000 pixels, if you scale it to have 1024x1024 pixels, the problem should be fixed. 512x512, 2048x2048, 512x1024, etc are also valid dimensions, the important thing is for each side of a texture to have power of two size.