High poly 3D models distort in Unity usually due to incorrect import settings (overcompression, misconfigured LOD) or hardware struggling with excessive polygon density.
Mesh compression reduces vertex precision, shifting vertices and distorting high-poly details—overdoing it warps fine features. Misconfigured LOD (Level of Detail) can also swap in low-poly versions incorrectly, causing sudden distortion.
Older GPUs may fail to render too many polygons smoothly, leading to artifacts.
Try disabling excessive compression or adjusting LOD in the model’s import settings first. If hardware is the issue, simplifying the model can help avoid distortion.