The model clearly has hard edges, but it still looks smooth. What's the matter?

[adamhahaEU2VH]

This model is imported through FBX.

The automatic smoothing setting of 0 is useless. It shows that the hard edges are really green and hard edges, and it is useless to press "hard" again.（as shown in Figure 2）

It is not a problem with smoothing groups. It is still the case when all smoothing groups are set to 1.

After UVW expansion, it is not a UVW problem.

This problem can be solved after Tessellate, as shown in Figure 3, but the problem is that I want to know why this happens and how to judge such smooth and wrong objects in a large scene through script (of course, I will study the script first)

Original, FBX importedAlthough the hard edge is displayed and I pressed the "hard" button, it is still wrongAfter Tessellate, the model is correct

[benjamin4MQAH · Accepted solution]

Try to reset normals - Edit Normals modifier, select all and click reset. Imported model from other applications can sometimes have broken or locked normals.

[adamhahaEU2VH]

Thank you. It's really a normal problem. Click to flip the normal.