Fix/lidar on chassis

assets/neoracer.xml

@@ -16,6 +16,11 @@
 
     <compiler angle="radian" autolimits="true"/>
 
+    <!-- Elliptic friction cone + high impratio: MuJoCo's recommended setting for
+         wheeled vehicles — stiffens tangential contact so the tires creep less
+         sideways (measured: full-lock radius 0.77 m → 0.74 m vs 0.68 m ideal). -->
+    <option cone="elliptic" impratio="10"/>
+
     <asset>
         <texture name="grid" type="2d" builtin="checker" width="512" height="512"
                  rgb1=".1 .2 .3" rgb2=".2 .3 .4"/>
@@ -77,7 +82,10 @@
 
     <worldbody>
         <!-- Ground plane; friction matches the wheels. -->
-        <geom type="plane" size="5 5 .01" material="grid" friction="1.5 0.1 0.1"/>
+        <!-- Ground plane; friction matches the wheels. size is render extent only
+             (collision plane is infinite) — 10 m half-extent so scenery like the
+             f1_track (reaches x~8, y~7) sits on grid with margin, not black void. -->
+        <geom type="plane" size="10 10 .01" material="grid" friction="1.5 0.1 0.1"/>
 
         <!--
         Car body. Spawn height = chassis half-height + wheel radius = 0.0806 + 0.050
@@ -117,10 +125,11 @@
             <site name="imu" pos="0 0 0" size=".01" rgba="1 1 0 1"/>
 
             <!--
-            LiDAR mount site, 0.15 m above the chassis centre (top of the stack).
+            LiDAR mount site, sitting on the top face of the chassis box
+            (half-height .0806) instead of floating 7 cm above it.
             Adjust the height to match CAD when available.
             -->
-            <site name="lidar_mount" pos="0 0 .15" size=".02" rgba="1 0 0 .5"/>
+            <site name="lidar_mount" pos="0 0 .0806" size=".02" rgba="1 0 0 .5"/>
 
             <!--
             LiDAR ray sites: 8 beams at 45° intervals in the horizontal plane.
@@ -137,17 +146,17 @@
             (single-wall placement test) to produce a correctly directional ring.
             Add more beams here (and matching rangefinders below) for richer RL obs.
             -->
-            <site name="lidar_000" pos="0 0 .15" zaxis="1.000000  0.000000 0" size=".005"/>
-            <site name="lidar_045" pos="0 0 .15" zaxis="0.707107  0.707107 0" size=".005"/>
-            <site name="lidar_090" pos="0 0 .15" zaxis="0.000000  1.000000 0" size=".005"/>
-            <site name="lidar_135" pos="0 0 .15" zaxis="-0.707107 0.707107 0" size=".005"/>
-            <site name="lidar_180" pos="0 0 .15" zaxis="-1.000000 0.000000 0" size=".005"/>
-            <site name="lidar_225" pos="0 0 .15" zaxis="-0.707107 -0.707107 0" size=".005"/>
-            <site name="lidar_270" pos="0 0 .15" zaxis="0.000000  -1.000000 0" size=".005"/>
-            <site name="lidar_315" pos="0 0 .15" zaxis="0.707107  -0.707107 0" size=".005"/>
+            <site name="lidar_000" pos="0 0 .0806" zaxis="1.000000  0.000000 0" size=".005"/>
+            <site name="lidar_045" pos="0 0 .0806" zaxis="0.707107  0.707107 0" size=".005"/>
+            <site name="lidar_090" pos="0 0 .0806" zaxis="0.000000  1.000000 0" size=".005"/>
+            <site name="lidar_135" pos="0 0 .0806" zaxis="-0.707107 0.707107 0" size=".005"/>
+            <site name="lidar_180" pos="0 0 .0806" zaxis="-1.000000 0.000000 0" size=".005"/>
+            <site name="lidar_225" pos="0 0 .0806" zaxis="-0.707107 -0.707107 0" size=".005"/>
+            <site name="lidar_270" pos="0 0 .0806" zaxis="0.000000  -1.000000 0" size=".005"/>
+            <site name="lidar_315" pos="0 0 .0806" zaxis="0.707107  -0.707107 0" size=".005"/>
             <!-- Cosmetic lidar mesh at the mount site. -->
             <geom name="vis_lidar" type="mesh" mass="0" mesh="vis_lidar"
-                  pos="0 0 0.15"
+                  pos="0 0 0.0806"
                   contype="0" conaffinity="0" rgba=".2 .2 .2 1"/>
 
             <!--