fixed crashes if bad object selections are made

scripts/addons/cam/exception.py

@@ -0,0 +1,2 @@
+class CamException(Exception):
+    pass

scripts/addons/cam/opencamlib/oclSample.py

@@ -12,6 +12,7 @@ from io_mesh_stl import blender_utils
 import mathutils
 import math
 from cam.simple import activate
+from cam.exception import *
 
 OCL_SCALE = 1000.0
 
@@ -32,8 +33,7 @@ def get_oclSTL(operation):
                 oclSTL.addTriangle(t)
         # FIXME needs to work with collections
     if not found_mesh:
-        operation.operator.report({'ERROR_INVALID_INPUT'},"This operation requires a mesh object")        
-        return None
+        raise CamException("This operation requires a mesh or curve object or equivalent (e.g. text, volume).")
     return oclSTL
 
 

scripts/addons/cam/ops.py

@@ -32,7 +32,7 @@ import shapely
 import mathutils
 import math
 import cam
-
+from cam.exception import *
 
 class threadCom:  # object passed to threads to read background process stdout info
     def __init__(self, o, proc):
@@ -201,7 +201,7 @@ class CalculatePath(bpy.types.Operator):
         if not o.valid:
             self.report({'ERROR_INVALID_INPUT'}, "Operation can't be performed, see warnings for info")
             print("Operation can't be performed, see warnings for info")
-            return {'FINISHED'}
+            return {'CANCELLED'}
 
         if o.computing:
             return {'FINISHED'}
@@ -210,8 +210,11 @@ class CalculatePath(bpy.types.Operator):
 
         if o.use_layers:
             o.parallel_step_back = False
-
-        gcodepath.getPath(context, o)
+        try:
+            gcodepath.getPath(context, o)
+        except CamException as e:
+            self.report({'ERROR'},str(e))
+            return {'CANCELLED'}
         coll = bpy.data.collections.get('RigidBodyWorld')
         if coll:
             bpy.data.collections.remove(coll)

scripts/addons/cam/utils.py

@@ -40,6 +40,7 @@ from cam.simple import *
 from cam.pattern import *
 from cam.polygon_utils_cam import *
 from cam.image_utils import *
+from cam.exception import *
 
 from cam.opencamlib.opencamlib import oclSample, oclSamplePoints, oclResampleChunks, oclGetWaterline
 
@@ -133,7 +134,8 @@ def getBoundsWorldspace(obs, use_modifiers=False):
             bpy.ops.object.delete()
             bpy.ops.outliner.orphans_purge()
         else:
-
+            if not hasattr(ob.data,"splines"):
+                raise CamException("Can't do CAM operation on the selected object type")
             # for coord in bb:
             for c in ob.data.splines:
                 for p in c.bezier_points: