Real cave passage walls are not straight lines and when you make a hand-drawn cave map, the passage walls are usually drawn as smoothly curving lines. As a result, the Viewer has passage modeling modes that simulate the smoothly curving passage walls of a hand-drawn map. You can activate this mode by selecting the “Open Spline Curve” option in the Passage Modeling window.
Spline Curves. The “Cubic Spline” is a mathematical function that draws smoothly curving lines. The Viewer uses Spline curves to simulate a hand-drawn survey map. If the left, right, up and down data is good, Spline curves will produce a very realistic cave map. Spline curves have three main disadvantages. First, because of the intense calculations involved, they are slow to draw. Second, they tend to average the passage wall dimensions, so the passage width and height may not be precisely accurate. Finally, bad data, high angle shots, contradictory dimensions and other oddities can create strange looking passage models.
