Sprite Floor Check

Hi there. I am following the 2D Paper Tutorial section 5 Blueprints setup. A check box called Use Flat Base For Floor Checks needs to be checked. I can’t find it. How may I achieve this in the current release of UE4. Thanks so much.

https://docs.unrealengine.com/en-us/Videos//PLZlv_N0_O1gauJh60307mE_67jqK42twB/zqkN_IIheRY

4:10 in the video.