Slicing.cpp: PrintObjectSlice.cpp: Allow changing printer to one with incompatible min/max layer height.

Author: themanyone

src/libslic3r/PrintObjectSlice.cpp

@@ -573,7 +573,7 @@ void PrintObject::slice()
             }
         });
     if (m_layers.empty())
-        throw Slic3r::SlicingError("No layers were detected. You might want to repair your STL file(s) or check their size or thickness and retry.\n");    
+        throw Slic3r::SlicingError("No layers were detected. Either variable layer height exceeded this printer's min/max layer height capabilities or STL file(s) need repair. Change sizes or thickness and retry slicing.\n");    
     this->set_done(posSlice);
 }
 

src/libslic3r/Slicing.cpp

@@ -642,7 +642,15 @@ std::vector<coordf_t> generate_object_layers(
                 const coordf_t z2 = layer_height_profile[next] * shrinkage_compensation_z;
                 const coordf_t h2 = layer_height_profile[next + 1];
                 height = lerp(h1, h2, (slice_z - z1) / (z2 - z1));
-                assert(height >= slicing_params.min_layer_height - EPSILON && height <= slicing_params.max_layer_height + EPSILON);
+                // FIXME: This function needs error return.
+                // Going to try aborting with empty {} instead of assert.
+                if (height < slicing_params.min_layer_height - EPSILON) {
+                    std::cerr << "Error: Layer height (" << height << ") below printer's minimum (" << slicing_params.min_layer_height << ").\n";
+                    return {};
+                } else if (height > slicing_params.max_layer_height + EPSILON) {
+                    std::cerr << "Error: Layer height (" << height << ") above printer's maximum (" << slicing_params.max_layer_height << ").\n";
+                    return {};
+                }
             }
         }
         slice_z = print_z + 0.5 * height;