I've tried
wireframeMesh.scaling = new BABYLON.Vector3(1.01, 1.01, 1.01)
But it doesn't work well because these two meshes will collide everywhere. @Deltakosh
Thanks for your suggestion, but "EdgeRender" is really slow when the model has millions of vertices, it takes about one minute to calculate edges. @SvenFrankson
When wireframe is enabled, the model becomes transparent. https://www.babylonjs-playground.com/#IUKB9V
I want the model to be solid in wireframe mode, like this demo with "See Through" disabled.