Hey pro ,about atmosphere ,i know i can opunhide it ,but theres must be a reason to delete it ,may have the faster solution now .any tips ?thanks

It says it's deprecated.

the atmosphere node was deprecated in the interest of removing fun.
Iso offset has very little to do with the atmosphere node, which was for running arbitrary code on top of the ray tracer, such as ray marching or path tracing.

You can still use fog shaders without the atmosphere node.

Add the render property “vm_pbrshader” to the mantra rop and specify your fogshader there. (after switching to pbr engine of course.)

This is a great method for implementing a custom path tracer or overriding the shading scene-wide, or writing out point clouds. All the things the atmosphere node was typically used for. (fog is not one of them)

I'm also bummed about this.