I just download the model from sketchfab,and the file format is .dae
Then I imported it into Blender 2.8 (The latest version “6-17”) ，I get all the
PBR textures there ,and add a simple sun light .You can see it’s ok in Eevee ,but
when I switch it to cycles ，the mesh is gone, anyone can tell me why it become this? plz…