# How to avoid intersections with a plane above a plane?

Hello I would like to have a main “ground” plane and other “road” planes above this main plane. When I use orbit control, I see confusion between the planes when the “road” objects are well above “ground” on the Y axis.

Here the minimal code to reproduce the problem :

How to solve this ?

If two planes have a distance of zero, use material polygonOffset to counter z-fighting.

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Hi, It’s not the case : “If two planes have a distance of zero”

But how do you do this ?
“use material polygonOffset to counter z-fighting.”

I agree with @rrrr_rrrr in that this seems to be a z-fighting issue. However, the ground plane is positioned at

`o.ground.position.y =` `-.7`

while the road(s) are positioned at

`o.road.dummy[i].position.set(0,` `.05,` `i * 20)`

so they both do not have the exact same elevation (y).

It looks like you are exhausting the resolution of the z-buffer. If you change the camera’s parameters like this:

`camera = new THREE.PerspectiveCamera(90, window.innerWidth / window.innerHeight,` `1, 500);`

the problem goes away.

Can you make a JSFiddle (https://jsfiddle.net/) illustrating the problem with two plane only.

mesh.renderOrder=-1;

I tested with your solutions one by one. To solve this, you have to use a combination of parameters:

In fact, you have to set the camera far to 1 and use a material that uses the polygonOffset…

Here is the codepen summarizing it all:

And here is what helped me get on the right track:

Actually that’s not true at all. See the camera setting and position of the planes in this attachment. Z-Fighting.html (5.0 KB)

It’s all about creating an offset between the planes ( GPU or CPU )

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