Gary are you dropping the effects on a super huge model? The default settings are geared towards smaller models. So for the Fan with default settings all you need to do is increase the Radius2 slider and you should see the default Fan. You probably should create a small 25x25 matrix to play with the effects. Once you know what they do then it will make it easier to make them work on a super huge whole house group model.
I understand what you mean, but it's weird how most models display at least
something on my whole house model--although it may not the right tool for the job (i.e. My while house isn't completely plastered with a grid of pixels--just rooflines and window/door outlines), but some do mostly nothing.
I've slated the issue to bugs, because something that sometimes happens with models is that I set up a model, start changing their settings/sliders to change how they look, and after 30 seconds of experimenting, on-screen representation of the model starts jumping around to acting as though the settings/sliders are back to where I started fiddling with them.
All in all though, even with some bugs and the learning curve, this is an awesome piece of software for the low, low, price of free!