traceback using different surface grid size

[Greg Couch]

From the command "surf grid 1":

Traceback (most recent call last):
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/cmd_line/gui.py", line 195, in execute
cmd.run(cmd_text)
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/commands/cli.py", line 2189, in run
results.append(ci.function(session, **kw_args))
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/commands/surface.py", line 154, in surface
threadq.apply_to_list(lambda s: s.calculate_surface_geometry(), args, nthread)
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/threadq.py", line 34, in apply_to_list
return [func(*a) for a in args]
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/threadq.py", line 34, in 
return [func(*a) for a in args]
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/commands/surface.py", line 154, in 
threadq.apply_to_list(lambda s: s.calculate_surface_geometry(), args, nthread)
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/atomic/molsurf.py", line 139, in calculate_surface_geometry
va, na, ta = surface.ses_surface_geometry(xyz, r, self.probe_radius, self.grid_spacing)
File "/home/gregc/src/chimerax/ChimeraX.app/lib/python3.5/site-packages/chimerax/core/surface/gridsurf.py", line 11, in ses_surface_geometry
pad = 2*probe_radius + radii.max() + grid_spacing
TypeError: unsupported operand type(s) for +: 'float' and 'NoneType'

[Tom Goddard]

Fixed.

Surface command grid_spacing option was broken by some changes I made last week.