Missing gen/environment.bazelrc when building patched Drake

[markisus]

I tried to build the patched version of Drake, as mentioned in the Readme. I reproduced the commands below.

git clone -b gcs2 git@github.com:mpetersen94/drake.git
mkdir drake-build
cd drake-build
cmake -DWITH_MOSEK=ON [-DWITH_GUROBI=ON -DWITH_ROBOTLOCOMOTION_SNOPT=ON] ../drake
make -j

The cmake command succeeded but the make command failed with the following error.

~/drake-build$ make -j
Scanning dependencies of target drake_cxx_python
[ 12%] Creating directories for 'drake_cxx_python'
[ 25%] No download step for 'drake_cxx_python'
[ 37%] No patch step for 'drake_cxx_python'
[ 50%] No update step for 'drake_cxx_python'
[ 62%] Performing configure step for 'drake_cxx_python'
[ 75%] Performing build step for 'drake_cxx_python'
[INFO 12:46:23.587 src/main/cpp/option_processor.cc:407] Looking for the following rc files: /etc/bazel.bazelrc,/home/mark/drake/.bazelrc,/home/mark/.bazelrc,/home/mark/drake-build/bazel.rc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /etc/bazel.bazelrc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/.bazelrc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/tools/bazel.rc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/tools/cc_toolchain/bazel.rc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/tools/dynamic_analysis/bazel.rc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/tools/lint/bazel.rc
[INFO 12:46:23.587 src/main/cpp/rc_file.cc:56] Parsing the RcFile /home/mark/drake/gen/environment.bazelrc
[FATAL 12:46:23.587 src/main/cpp/blaze.cc:1302] Unexpected error reading .blazerc file '/home/mark/drake/gen/environment.bazelrc': (error: 2): No such file or directory
make[2]: *** [CMakeFiles/drake_cxx_python.dir/build.make:112: drake_cxx_python-prefix/src/drake_cxx_python-stamp/drake_cxx_python-build] Error 37
make[1]: *** [CMakeFiles/Makefile2:860: CMakeFiles/drake_cxx_python.dir/all] Error 2
make: *** [Makefile:163: all] Error 2

It seems I don't have the file drake/gen/environment.bazelrc. Judging by the filepath, I'm guessing this file is auto-generated by the build system? In any case, I checked manually and this file was not present.

[Zhang-Haiming]

I meet the same error, have you solved it?

[markisus]

@Zhang-Haiming I found a workaround by simply using the latest Drake version. It has all you need to decompose your collision free space into convex regions in joint space. Then, instead of using the shortest paths through convex sets, I tried a heuristic that runs way faster and gives good results.

1. Create your own undirected graph. Each pairwise intersection between convex sets is a node, which represents the center of this intersection. Nodes are connected by an edge if they live in the same convex set. The edge cost is the squared norm, or some other distance metric of your choosing.
2. Run Djikstra on this graph.
3. Take nodes on the optimal path and fit a B-spline. This curve will be collision free if your original convex sets were.
4. Use Toppra (included in Drake) to compute the necessary joint accelerations to travel through the path.