At this point there isn't any distance filter for Solid Modeling but if you're only interested in a ribbon through the model it may not make a difference.
You could increase the Horizontal Weighting Exponent in the Inverse Distance Weighting algorithm.
Another option would be to run your model through the Solid/Filter/Distance Filter.
One other technique that would be to first create your model based on G value, then create a model based on the Distance To Point (D2P) algorithm. You could then convert the D2P model into a boolean model and use that modify your G value model with Solid/Math.
Mitch Wolberg,
RockWare, Inc.