I developed 3d model with 3dsmax. enter image description here

But I have some issue. I got this issue when import 3d model(FBX) to unity. enter image description here

enter image description here

As you can see, model showed strangely.

Solution 1

you need to normalize and flip your normals.

download and install Blender 3D

import your fbx model, then in the mesh editor (default screen) recalculate your normals and then export your model into fbx again (always make a backup of your original file before you export, just to be safe)

tutorial

Solution 2

or you can disable backface culling on that 3d model in the renderer component