I have a project created with Archcad 25 and exported it to Twinmotion with Datasmith plugin. After customizing the project inside twinmotion, I executed the Resource Collector to gather all maps inside the project folder.
After some days I made some changes in the original file inside Archicad and hit the synchronize button in Datasmith pallet.
The project inside twinmotion, got completely messed up, because many of the materials now are shown as white objects. The missing materials windows does not present any missing materials although it seems that for many objects the program cannot find the original material that initially was bind with.
The problem is only happening after the Resource Collector execution. Before that the updating process is working properly.
It is definitely a bug inside Twinmotion. I opened again the project inside Twinmotion with all the materials having a white surface, and temporarily changed the quality settings from Ultra to High and pressed ok. All the objects recovered their material surface. Then turned back the setting to Ultra.
In fact before that, I tried changing slightly any of the materials settings and again recovered the surface map for the selected object. But the trick with the quality settings brings the missing materials on screen all together.
Thank you for posting in the community and sorry to hear about the troubles. Would you be able to contact us directly to report this behavior so we can properly investigate. Here is the link to do so: https://twinmotionhelp.epicgames.com/s/case-community-page