use venv when creating a new project or opening an existing one

Pycharm 4 appears to try to load the requirements.txt file when creating a new project or when the file has changed (right?). Great feature. Is there something similar in automatically finding a virtual environment, say a 'venv' directory in project root? The documentation tell me how to create a new local virtualenv using the UI and how to select the Project Interpreter, but not if there's an automatic selection. Please advise. Thanks.