Error: material 'Black' is not unique

[kruusamae]

i work only with xarm7 but, by looking at the xacro files, i expect the behavior to be the same for all xarms. everything works just fine when you work with only one robot. but if you create a system with multiple robots (e.g., a xacro file that includes two xarm7s on a tabletop) and start parsing the xacro, there will be an error along the lines, "material 'Black' is not unique." this happens because materials Black, Red, White, and Silver are defined (without prefix) in xarm7.urdf.xacro. easiest fix to the issue would be to add ${prefix} to wherever materials are defined and used, i.e., in files xarm7.urdf.xacro, xarm6.urdf.xacro, and xarm5.urdf.xacro. however, i am not sure if this is the most intelligent way to fix the issue. any feedback from the maintainers would be much appreciated!

[penglongxiang]

@kruusamae Thanks for your discovery and suggestions, we will take it into consideration and fix in the next update.