vue-cesium – how reduce the height of the 3d tiles layer relative to the ground?

vue-cesium – how reduce the height of the 3d tiles layer relative to the ground?
here is my vue 3 component:

<template>
  <vc-viewer>
    <vc-layer-imagery>

      <!--      this is a ground layer-->

      <vc-imagery-provider-bing
        ref="provider"
        bm-key="AmGu3cvB_g1HbkQErEyvmLc9j0YIGWS7IdOqR7-hQbO8J92Fzrzkhy_bYKSsyoEx"
        :map-style="'AerialWithLabels'"
      ></vc-imagery-provider-bing>

      <!--      this is a 3d tiles layer, i need to reduce its height-->

      <vc-primitive-tileset
        :url="'https://lol/3d/new_form/tileset.json'"
        :maximum-memory-usage="4096"
        :maximumScreenSpaceError="4"
      ></vc-primitive-tileset>
    </vc-layer-imagery>
  </vc-viewer>
</template>

this is what my problem looks like – the layer is “flying in the air”:
screenshot

I would like the 3d layer to be at ground level or below