I still have this issue, if the fallback relative error in SM details is set to 1, then the fallback mesh will successfully generated and got some ‘detail removed’ as the document is mentioned. AFAIK for perhaps all the situations that not supporting nanite, nanite mesh will use the fallback mesh for rendering, even if bDisallowNanite is set as true in SMC’s details it shows fallback mesh as well. What i’m looking for is if we can use back to the original mesh at runtime when nanite is disabled in any situations(not supported or autonomy), May have a better solution than copied mesh.