Add Signed Distance Field to collision geometries.

PiperOrigin-RevId: 557507088
Change-Id: I358a642407aee1ba8dfc9d405eb9a4f609435fe9

model/plugin/sdf/scene.xml

@@ -0,0 +1,38 @@
+<!-- Copyright 2021 DeepMind Technologies Limited
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<mujoco>
+  <compiler texturedir="asset"/>
+
+  <statistic meansize=".05"/>
+
+  <visual>
+    <rgba haze="0.15 0.25 0.35 1"/>
+    <map stiffness="700" shadowscale="0.5" fogstart="1" fogend="15" zfar="40" haze="1" shadowclip="3"/>
+  </visual>
+
+  <asset>
+    <texture type="skybox" builtin="gradient" rgb1="0.3 0.5 0.7" rgb2="0 0 0" width="512" height="512"/>
+    <texture name="texplane" type="2d" builtin="checker" rgb1=".2 .3 .4" rgb2=".1 0.15 0.2"
+      width="512" height="512" mark="cross" markrgb=".8 .8 .8"/>
+
+    <material name="matplane" reflectance="0.3" texture="texplane" texrepeat="1 1" texuniform="true"/>
+  </asset>
+
+  <worldbody>
+    <light directional="true" diffuse=".8 .8 .8" specular="0.2 0.2 0.2" pos="0 0 4" dir="0 0 -1"/>
+    <geom name="ground" type="plane" pos="0 0 -.02" size="10 10 .01" material="matplane" condim="1"/>
+  </worldbody>
+</mujoco>