[realsense2_description] Add docs and build system

BUILD.bazel

@@ -4,6 +4,14 @@ load("@bazel_skylib//rules:diff_test.bzl", "diff_test")
 load(":defs.bzl", "xacro_file")
 
 _XACROS = {
+    "realsense2_description/urdf/d415.urdf": {
+        "src": "realsense2_description/urdf/customized/test_d415_camera.urdf.xacro",
+        "data": [
+            "realsense2_description/urdf/customized/_d415.urdf.xacro",
+            "realsense2_description/urdf/customized/_materials.urdf.xacro",
+            "realsense2_description/urdf/customized/_usb_plug.urdf.xacro",
+        ],
+    },
     "tri_homecart/homecart_bimanual.urdf": {
         "src": "tri_homecart/homecart_bimanual.urdf.xacro",
         "data": [],
@@ -37,3 +45,27 @@ _XACROS = {
     )
     for name in _XACROS
 ]
+
+# Patch the realsense files to suit this repository.
+[
+    genrule(
+        name = "_gen_{}".format(filename),
+        srcs = [
+            "realsense2_description/urdf/customize.sed",
+            "realsense2_description/urdf/{}".format(filename),
+        ],
+        outs = [
+            "realsense2_description/urdf/customized/{}".format(filename),
+        ],
+        cmd = "sed --file={} {} > $@".format(
+            "$(execpath realsense2_description/urdf/customize.sed)",
+            "$(execpath realsense2_description/urdf/{})".format(filename),
+        ),
+    )
+    for filename in [
+        "test_d415_camera.urdf.xacro",
+        "_d415.urdf.xacro",
+        "_materials.urdf.xacro",
+        "_usb_plug.urdf.xacro",
+    ]
+]

realsense2_description/README.md

@@ -0,0 +1,10 @@
+# Intel RealSense cameras
+
+This folder contains models of the Intel RealSense cameras.
+
+The models were originally published by Intel here
+ https://github.com/IntelRealSense/realsense-ros
+but have been further customized for use by Drake, e.g., changing the
+mesh paths and mesh file formats.
+
+Drake's models are based on v4.54.1 from the Intel repository.

realsense2_description/urdf/customize.sed

@@ -0,0 +1,10 @@
+# Note that $(...) stuff in the below is NOT special regex characters, we are
+# actually matching the xacro text like "$(arg use_mesh)" literally.
+
+s|$(find realsense2_description)/urdf/||;
+s|file://$(find realsense2_description)/meshes/|../meshes/|;
+s|$(arg use_mesh)|true|;
+s|$(arg use_nominal_extrinsics)|false|;
+s|$(arg add_plug)|false|;
+s|package://realsense2_description|package://drake/manipulation/models/realsense2_description|;
+s|\.stl|.obj|;

realsense2_description/urdf/d415.urdf

@@ -1,6 +1,6 @@
 <?xml version="1.0" ?>
 <!-- =================================================================================== -->
-<!-- |    This document was autogenerated by xacro from external/intel_realsense_ros_internal/realsense2_description/urdf/test_d415_camera.urdf.xacro | -->
+<!-- |    This document was autogenerated by xacro from bazel-out/k8-fastbuild/bin/realsense2_description/urdf/customized/test_d415_camera.urdf.xacro | -->
 <!-- |    EDITING THIS FILE BY HAND IS NOT RECOMMENDED                                 | -->
 <!-- =================================================================================== -->
 <robot name="realsense2_camera">