If your URL pattern looks like:
`urlpatterns = patterns('django.views.generic.create_update',
url(r'^obj/(?P<obj_id>\d+)/new_thing$', create_object, {'form_class': ThingForm, 'template_name': 'thing/new_thing.html', extra_context: {:this":"that"}),
)`
You will receive an error, because the create_update view doesn't have a parameter called "obj_id". Supposing you want that variable in the URL, and furthermore let's say you wanted to do something with it in the template. With this function, you can wrap the view, and add the parameter capture_to_context, which maps URL variables to template variables:
`urlpatterns = patterns('django.views.generic.create_update',
url(r'^obj/(?P<obj_id>\d+)/new_thing$', view_url_vars_to_context(create_object), {'form_class': ThingForm, 'template_name': 'thing/new_thing.html', 'url_vars_to_context':{'obj_id':'objID'}, extra_context: {:this":"that"}}),
)`
Now objID will be a variable in your template, with the value given to obj_id.
This is good for generic views, but there's no reason you couldn't use it for your own views if you really wanted, as long as you had an "extra_context" parameter.