Why does the weird overlapping lines appear when the camera is far? when the camera is near, it is all ok

[kong2dog]

when camera is far

when camera is near

[mjurczyk]

Could be z-fighting or shadow acne - try disabling shadows in the scene first and see if it helps.

[kong2dog]

I disabled shadowMap on renderer, but the problem still exists

[mjurczyk]

Are there multiple models in the scene? If yes, is there a chance they are relatively close by one another? If yes, try increasing / decreasing camera near and far values.

[kong2dog]

Thank you, I will try to figure it out.

[kong2dog]

after I adjust the camera far from 100000 to 5000, it is ok now

[mjurczyk]

Depth precision is large, but still limited. So when you increase the difference between near and far plane too much, objects and faces will start fighting with one another for the rendering order (since only one thing can be rendered at a specific depth, increasing far parameter increases the range of depth but lowers the amount of discrete depth steps within that range.)

If you need to render super large distances - you can also consider switching to logarithmic depth - that way you can render a wide range of objects at different scales and distances, without worrying about z-fighting.