cura preview problem

[mpoyl 0]

because it looks like this to me and the lines are not visible????

[GregValiant 1,301]

That looks like you are in Compatibility Mode.  Cura defaults to that when the video system doesn't support OpenGL 4.0, or the Computer doesn't assign Cura to a more capable video sub-system (if there is one), or, the Preferences / Configure Cura/ Viewport Behavior setting "Force Layer View Compatibility Mode" is ticked.  If it's on then turn it off.

The other two are harder to fix.  It could be your operating system or your video drivers.

[mpoyl 0]

this problem only cura?? SuperSlicer no problem

[GregValiant 1,301]

This is with compatibility mode turned on.  This 2D rendering has some advantages.

 

This is with it turned off.  This 3D rendering has some advantages.

 

If your system has dual video systems and an app like the Nvidia Control Panel then you can set it to allow Cura to use the more capable video system and you should get the 3D rendering.

If SuperSlicer doesn't require OpenGL 4.0, and your system doesn't support OpenGL 4.0, then yes, SuperSlicer could render in 3D and Cura in the flat view.