mujoco

<mujoco model="Reflection: PBR metallic + ORM">
  <!-- Minimal planar-reflection bed for the two PBR reflect paths:
         floor  -> pbr_reflect        (metallic/roughness on a plane)
         mirror -> pbr_packed_reflect  (occlusion/roughness/metallic texture)
       See reflection.xml for the full integration scene. -->

  <asset>
    <texture name="sky" type="skybox" builtin="gradient" rgb1=".18 .22 .30" rgb2=".55 .58 .62" width="32" height="512"/>
    <texture name="ibl" type="cube" builtin="gradient" rgb1=".32 .35 .40" rgb2=".58 .56 .52" width="32" height="32"/>
    <texture name="grid" type="2d" builtin="checker" rgb1=".05 .06 .09" rgb2=".42 .45 .50" width="300" height="300"/>
    <!-- packed occlusion(R)/roughness(G)/metallic(B): smooth metal -->
    <texture name="orm" type="2d" builtin="flat" rgb1="1 .3 1" width="8" height="8"/>
    <material name="floor"  texture="grid" texrepeat="3 3" texuniform="true" metallic=".5" roughness=".25" reflectance=".35"/>
    <material name="mirror" rgba=".95 .64 .38 1" reflectance=".9">
      <layer texture="orm" role="orm"/>
    </material>
    <material name="post"   rgba=".82 .16 .16 1"/>
    <material name="ball"   rgba=".20 .68 .30 1"/>
  </asset>

  <worldbody>
  <camera name="default" pos="3.515 -1.039 1.177" xyaxes="0.229 0.973 0.000 -0.102 0.024 0.995"/>
    <light pos="1.5 0.6 2.6" dir="-0.6 -0.2 -2" cutoff="55" range="20" intensity="800000"
           castshadow="true" ambient=".1 .1 .12" type="spot"/>
    <light type="image" texture="ibl" intensity="8000"/>

    <geom name="floor"  type="plane" size="3 3 .1" material="floor"/>
    <geom name="mirror" type="box"   size="1.0 0.7 0.02" material="mirror" pos="-1.2 0 0.7" zaxis="1 0 0"/>
    <geom name="post"   type="box"    material="post" size=".05 .05 .5" pos="0 0 0.5"/>
    <geom name="ball"   type="sphere" material="ball" size=".22" pos="0.4 -0.5 0.22"/>
  </worldbody>
</mujoco>