Spline is displayed in both sides of the mesh

We have a 3D mesh that the user can select to draw splines on it. The splines are not added as children of the mesh, but as different objects that get the same points as the specific location where it was drawn on the mesh. These objects are added to a group that is added to the same scene of the mesh.
Both the mesh and the splines are set with transparent=true.
The problem is that when creating a spline, it is visible from both sides of the mesh. We want it to be visible only on the side of the mesh on which it was created, not on the other side of the mesh.

We tried to change the transparent value, the render order and the depth but nothing helped.

How can we achieve this?

Thanks!

Thanks for updating your post with additional information!

However, it would be easier to investigate your issue if you would demonstrate it with a live example.

Right now, it seems your problem can’t be solved by a specific configuration. You probably have to figure out with a custom check when the splines should be rendered or not. This requires that the application knows when the camera faces the “correct side” of your mesh.