1. Create Sphere and select the row of segments that you want the tube to follow in its extudetion and select points. (Fig. 1) 2. Copy the points to layer two. Select a segment from the area that the tube is to extrude around and copy it to layer three. (Fig.2) 3. Draw out the shape of the tube perpendicular to the surface of the sphere. (Fig.3) 4. With the segment in layer there in the background and the shape of the tube in the forground you can slice the part of the tube that would be inside the sphere. (Fig.4) 5. Return to layer two. This is where we start to make the series of steps that will be used to morph the extrudsion around the Sphere. 6. Select the points, starting at the point, the shape of the tube is located. Then use the Ctrl p key (make curve) combination to make a curve. (Fig.5) 7. With the tube shape in the foreground and the newly created curve in the 'background, use the Ctrl r (rail extrude). This will bring up the panel for single rail extrude. I've used Uniform Knots and a number 15 for the number of knots in the curve. Using Automatic will give you more segments in the extrudsion. (Fig. 6) Note the direction of surface normal. Pointing away from the direction of normal. Pointing away from the direction of the normal. Pointing away from the direction of the extrudison will cause the surfaces to be pointing out. 8. Click Ok to create the extrusion. (Fig.7) NOTE It is not a full 360 rotation. 9. Make a second curve by selecting the last point and the first point in layer two (Ctrl p) and copy it to layer 5. Return to layer 4, select the end polygon and rename the surface to something different than the tube. 10. With the new curve in layer 5, in the background use Crtl r to extrude the shape one knot (Fig.8) 11. The result should look like (Fig.9). 12. Select the end polygon and position it close to the beginning polygon (if you need a full 360 extrudsion). (Fig.10) 13. Once selected use Ctrl v and set the value for 0° on the Z axis.(Fig.11) NOTE disreguard Step 13 and Fig.11 is an Amiga layout screen in 8 colors 800 x 600 Picasso II Board on an C 1950 monitor. 14. Now that the easy parts out of the way, it's time to roll up your sleves and get to work. What we have here is the end result of the extrudsion a full 360°. I'll be morphing the tube two sections at a time. Using nime objects from start to finish. So save this as Tube9. NOTE the next eight objects will be Tube8 Tube7 etc. 15. We'll be working backwards, with polygon selected at the bottom of the screen use the w key to open the Polygon Statistics Panel and select the end polygon's name, created in Step 9. (Fig.12) 16. You'll now have the last set of polygons highlighted, deselect all but the end polygon. (Fig.13, 14) 17. Move the polygon back to the previous row of points. (Fig.15) 18. Select the polygons on both ends of the tube, you have three, use the z key to cut them out, then rename the tube (Fig.16) 19. Select points at the bottom of the screen and highlight the two set of points. (Fig.17) 19. Position these points with the next previous points. (Fig.18) 20. Now save this as Tube8. 21. Select all the points and move them to the next previous row. Repeat this again and then Save as Tube7. (Fig.19) 22. Continue, repeating Step 21 until you end up with one polygon. (Fig.20) You should now have nine Tube objects, Tube1-9, and a Sphere. 23. Go to Layout, load your Sphere and the nine Tubes and morph from 1 to 9. This might not be the best way of extruding a tube around a sphere, it works for me. Increase the number of knots in each of the Tube segments for a smoother tube. In either case it might help someone to understand rail extrudison. I didn't use a closed curve, as that would have just made a toris with no way of opening it, to start compressing the tube back on itself. Good luck. Stephen Nevins onlynev@eskimo.com OnlyNev Bru Ha Ha Productions 1 (206) 823-8540