add warning if total parametric volume is less then 1

6 jobs for master in 8 minutes and 26 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #130314
Linux
clang-c++11

00:04:07

passed #130318
Linux
clang-c++14

00:08:25

passed #130312
Linux
gcc-c++11

00:02:06

passed #130316
Linux
gcc-c++14

00:01:56

passed #130320
Apple
macos-c++11

00:02:56

passed #130321
Apple
macos-c++14

00:05:13