A system (100, 100B, 100C, 200, 300, 325, 400, 500, 700, 800) for outputting haptic effects comprising: a first sensor configured to detect a user interaction with a touch surface (116, 202, 402, 502, 702, 802) and transmit a first sensor signal associated with the user interaction; a second sensor (130, 704) configured to detect a feature and transmit a second sensor signal associated with the feature; a processor in communication with the first sensor and the second sensor, the processor configured to: determine a first haptic effect based on the user interaction; determine a modified haptic effect based at least in part on the first haptic effect and the feature; output a haptic signal associated with the modified haptic effect; and a haptic output device (118, 218, 222) in communication with the processor and coupled to the touch surface (116, 202, 402, 502, 702, 802), the haptic output device configured to receive the haptic signal and output the modified haptic effect to the touch surface; characterized in that the second sensor comprises two force sensors configured to detect a lateral force that the user applies in directions generally parallel to the touch surface (116, 202, 402, 502, 702, 802) and a normal force that the user applies in a direction generally normal to the touch surface (116, 202, 402, 502, 702, 802); the processor is configured to use the lateral force and the normal force together to determine a frictional force or a coefficient of friction between the user and the surface of the touch surface (116, 202, 402, 502, 702, 802); and the processor is configured to vary a friction or a texture of the first haptic effect by using the determined frictional force or coefficient of friction. a first sensor configured to detect a user interaction with a touch surface (116, 202, 402, 502, 702, 802) and transmit a first sensor signal associated with the user interaction; a second sensor (130, 704) configured to detect a feature and transmit a second sensor signal associated with the feature; a processor in communication with the first sensor and the second sensor, the processor configured to: determine a first haptic effect based on the user interaction; determine a modified haptic effect based at least in part on the first haptic effect and the feature; output a haptic signal associated with the modified haptic effect; and a haptic output device (118, 218, 222) in communication with the processor and coupled to the touch surface (116, 202, 402, 502, 702, 802), the haptic output device configured to receive the haptic signal and output the modified haptic effect to the touch surface; characterized in that the second sensor comprises two force sensors configured to detect a lateral force that the user applies in directions generally parallel to the touch surface (116, 202, 402, 502, 702, 802) and a normal force that the user applies in a direction generally normal to the touch surface (116, 202, 402, 502, 702, 802); the processor is configured to use the lateral force and the normal force together to determine a frictional force or a coefficient of friction between the user and the surface of the touch surface (116, 202, 402, 502, 702, 802); and the processor is configured to vary a friction or a texture of the first haptic effect by using the determined frictional force or coefficient of friction. determine a first haptic effect based on the user interaction; determine a modified haptic effect based at least in part on the first haptic effect and the feature; output a haptic signal associated with the modified haptic effect; and a haptic output device (118, 218, 222) in communication with the processor and coupled to the touch surface (116, 202, 402, 502, 702, 802), the haptic output device configured to receive the haptic signal and output the modified haptic effect to the touch surface; characterized in that the second sensor comprises two force sensors configured to detect a lateral force that the user applies in directions generally parallel to the touch surface (116, 202, 402, 502, 702, 802) and a normal force that the user applies in a direction generally normal to the touch surface (116, 202, 402, 502, 702, 802); the processor is configured to use the lateral force and the normal force together to determine a frictional force or a coefficient of friction between the user and the surface of the touch surface (116, 202, 402, 502, 702, 802); and the processor is configured to vary a friction or a texture of the first haptic effect by using the determined frictional force or coefficient of friction.