I have not been able to create an intersection layer in QGIS 3.0. The method has been working fine in QGIS 2.18. The method I have been using is to select Vector >> Geoprocessing tools >> Intersection. I then choose the Input layer and Intersect layer from the dropdown menu, and click on Run. In QGIS 2.18 it works fine. In QGIS 3.0 I get the error:
Traceback (most recent call last): File "C:/PROGRA~1/QGIS3~1.0/apps/qgis/./python/plugins\processing\algs\qgis\Intersection.py", line 135, in processAlgorithm indexB = QgsSpatialIndex(sourceB.getFeatures(QgsFeatureRequest().setSubsetOfAttributes().setDestinationCrs(sourceA.sourceCrs(), context.transformContext())), feedback) Exception: unknown. Execution failed after 0.23 seconds
Is there is setting in QGIS 3.0 that I need to select?