CompuServe Thread

Chris, As you requested, I will now try to explain my method for constructing the CORKSCREW.SEG I sent you. Please keep in mind that much of what follows can easily be changed to create other corkscrew like SEGs. First set the left window to FRONT view and the right window to TOP view. Then use the APPEND function to load CIRCLE.SEG, a looped spline made of four control points, from Hash's primitives collection into both views. If CIRCLE.SEG is lying flat in the FRONT view, you will have to rotate it around the x-axis 90 degrees so that you can see it in all of its glory. Now set grid spacing to about 50 (you will probably have to experiment with this number to find one that works for you). Then turn on the grid. Select all of the control points in CIRCLE.SEG and move it to the left of the pivot about 5-10 grid spaces. Change lathe precision to 12 and then lathe CIRCLE.SEG. You should now have a segment that looks like a tire inner tube. In the TOP view, notice how the 12 circular splines resemble a clock face. This will help in the explanation that follows. Go to the TOP view and use the BREAK function to remove the splines that connect the circular splines between the 11 and 12 o'clock positions. You may have to switch to the bottom view to BREAK the splines on the bottom. Now while in the TOP view use the GROUP function to select all of the circular splines except for the one at the 12 o'clock position. Then turn off both the x and z-axis translation buttons. Go to the FRONT view and move the now selected splines down the y-axis about 1 grid space. After that go back to TOP view and use the GROUP function to un-select the circular spline at the 1 o'clock position leaving the rest selected. Now go back to the FRONT view and move the selected control points down the y-axis 1 grid space. Continue this process until you run out of circular splines. Once you have moved the circular spline at 11 o'clock to its final position, the rest is easy. When all of the circular splines have been moved, you will need to select all of the control points that make up the segment. Then use the CLONE function to make a copy of the segment. While in the FRONT view move the copy down the y-axis until the top of the copy is about 1 grid space below the original segment. Now deselect all control points. Switch to a view that will allow you to see the gap between the original and copy segments. Then go in and connect the two segments with splines made of 2 control points(this is important for a smooth connection). By this point the corkscrew shape should be apparent. To create a longer corkscrew shape just continue the copy and connect technique. I hope this explanation was helpful. If you have any questions let me know. Chris D.