How to load oblique photography without being blocked by terrain

viewer.scene.globe.depthTestAgainstTerrain = true
const tplTileset = await Cesium.Cesium3DTileset.fromUrl('http://localhost/uploadFiles/tileset.json', {
    maximumScreenSpaceError: 1,
    backFaceCulling: false,
})
viewer.scene.primitives.add(tplTileset);
I have loaded a 3D Tileset,However, I can only see part of it. I noticed that the effect of a client is very good, and it won't be obstructed. It seems like the terrain where the model is located has been hollowed out. How can I achieve this effect in Cesium