Is it possible to really touch something in VRML, not just have a texture map that looks like a touchable surface?
This depends on whether you have the appropriate hardware to give you what’s known as haptic or force-feedback.
At the moment, because this area is so new, there are no haptic nodes in VRML 2.0. But you could use the PROTO mechanism to make a local, proprietary node to support them just for your equipment.
Within your custom PROTO, you can include a script that manages your PROTO contents and uses Java or the External Authoring Interface to pass the information from the PROTO out to your tactile output device driver. For instance, you could include a one-channel VRML Texture node, to be interpreted as a grey-scale bump map.
Of course there’s a lot more to it than this. There are the issues of how textures, geometry and dynamics interact to produce the sensation of touch. Evan Wies is working on what he describes as “a seamless, VRML2.0-compliant approach that combines PROTOs and scripts. It will work with the Sensable Technologies’ Phantom, and Immersion’s Impulse Engine and I-Force platforms. It should work with any browser that is ‘up-to-spec.'”