Rendering Sharp Polygons

[Liakoz]

I downloaded a free arms rig from a youtube video.I deleted the arms model and i put my own.The arms rig says that its made in 3ds max student version and shows a warning.When i render my arms model it appears like in the photo with very sharp polygons.In a different file without the rig,the arms render perfectly...why is that?

[maru]

This looks like an incorrectly set up normal map. Please see: https://coronarenderer.freshdesk.com/support/solutions/articles/5000501663-corona-normal-map

[Liakoz]

Thanks for the answer,but the model's polygons got weird for some reason when i imported the "rig max file".After several 3ds max crashes i managed to import the "arms" into the "rig max file" and they are ok now.

[romullus]

It could be that the vertex normals got corrupted after import.

[aaouviz]

To my eye it looks like you have double surfaces going on? Could very well be wrong, though of course.