NormalAttrib: default props to 0 instead of undefined

9 jobs for normalattrib-initialize-0 in 4 minutes and 25 seconds
Status Job ID Name Coverage
  Test
passed clang-c++11 #75648
Linux

00:04:10

passed cppcheck #75650
Linux

00:04:25

passed doc #75655
Linux

00:00:19

passed gcc-c++11 #75647
Linux

00:02:57

passed macos-c++11 #75649
Apple

00:01:37

passed VS2015-32-bit #75654
VS2015

00:01:16

passed VS2015-64-bit #75653
VS2015

00:01:23

passed VS2017-32-bit #75652
VS2017

00:01:08

passed VS2017-64-bit #75651
VS2015

00:01:29