Advanced Crisscross Ring
Precise Surface Modeling techniques, together with tricks for using UV Curves and Flow Along the Surface, create this advanced ring.
Create a Dome Ring with an inset surface that ends at a “V” at either end. Extract the inset surface and re-create it with curves so it is a single, untrimmed surface. Extend it, and Project “V” curves onto it. Lay this surface flat with Create UV Curves, and model lattice work onto it. Create a “Base Surface” from the original UV curves, and use Flow Along Surface to get this onto the ring. Gem Loader with the OnSurface Option and Gems on a Curve with the “Show Prongs” option will complete this ring.
Icon Key:
1. Place a Ring Rail
Select a size for this ring using the Ring Rail tool from the Tools menu. Click the green arrow to place it in the viewports.
2. Add Outside Rail
Click Start within the Outside Rail tool to place a rail in the viewports. This rail will just follow the side (front/back) of the ring – not the top! So adjust the Viewport Control Handles or Builder controls to set the size to about 1 mm at the bottom, 1.3 mm at the sides, and 1.5 mm at the top.
3. Inside Profile, Line
Using the Line tool with the “BothSides” option, starting the Quad O-Snap at the bottom of the inside rail, extend a line out to both sides in the Side View viewport to represent the inside, bottom width of the ring as seen in this view (about 5 mm total).
4. Side View Shape of Ring
Using the Line tool again, create a line in the Side View viewport that represents the side taper of the ring in this viewport. Extend these beyond the top of the outside finger rail as seen in this view. Mirror this curve to the other side of F4 to create the other side of the ring.
5. Extend Command
Use the Extend command, found in the Curve menu, to extend these curves down past the bottom of the outside finger rail. Extend each curve in this manner.
6. Curve from 2 Views
Use Curve from 2 Views, 2 times, between the Side View curves representing the taper and the inner and outer finger rails. Mirror curves around F4 to create the corresponding set.
7. Duplicate in Place
Select the two planar (flat) Side View curves and run the Duplicate command with the “InPlace” option selected in the Command line. Select one set of curves, place it on the gray layer color, and turn it off (turn it on again to Job Bag all curves).
8. Split to Create Profile
Select the remaining Side View curves and Split them with the new curves created in Step 6. The four small curves that result will become your profile, so place them onto Creation Yellow for better organization of your modeling processes.
9. Complete with Line, Arc
Complete both profiles by connecting the two sides of the top profile with the Line tool. Then, create the “tops” of both profiles using the Arc Direction tool twice, creating the shape you want at the top and bottom of the ring.
10. “Sweep 4” & Join
To create the surface when there are four rails and four (unjoined) profile curves, each of which touches the rails perfectly, we run four Sweep 2 operations – a function we refer to as “Sweep 4”. So, select each pair of rails and run Sweep 2 on them with the profiles that touch them. Repeat until all sides of the ring have been made. Join only the inside three surfaces of the ring, leaving the outside surface separate.
11. Draw a Cutting Shape
Retrieve the two curves saved on the gray layer in Step 7 (or Extend the two you split!) and Offset one in the Side View viewport to the distance you want between the inset surface and the edge of the ring. Mirror the new curve (it should extend past the top of the ring) and draw a Line (or Arc, your choice!) to create the bottom of the inset surface. Mirror this, and select all curves. Trim away all but cutting shape &Join.
12. Project & Split
Still working in the Side View viewport, select the Project tool and select the curve drawn in Step 11 as the object to Project. The surface of the ring (select it in Side View) is the object onto which to project the curve. Select the surface and run the Split command. The curve you just projected onto the surface is the object with which to Split it.
13. Scale 2D & 1D
Select the surface you just split away and 2D scale it smaller, from F4, in the Looking Down viewport. This makes it smaller and pushes it just below the surface in the Through Finger view. Run 1D in Side View now, from the bottom of the surface straight up (with Shift), and scale it down in height until you like the results.
14. Loft Edges & Join
To create the “side walls” of the inset surface, run the Loft command between each corresponding “poly surface edges” on the inset and outside ring surfaces. Join all surfaces of the ring together, checking the command line to ensure that “one closed poly surface” was created.
15. Extract, Dup Border
Extract just the inset surface and run Duplicate with the “InPlace” option selected in the Command line again. Join one copy to the rest of the ring. Hide or turn off the ring for assistance. Explode the poly surface into its component surfaces. Select both surfaces and, using a new layer color, run Dup Border to create a curve around all edges of the surface.
16. Extract Isocurve
Extract an isocurve from this surface right at the End O-Snap representing the “kink” in the surface where the “V” shape meets the edge. Mirror this to the other side of the surface, using F4 as the “Start of Mirror Plane and Shift to engage Ortho.
17. Rebuild, Sweep 2
Delete the surface (!!) and Join the two curves representing the “long edges” of the surface. Rebuild this curve. Then, run Sweep 2, with these as and the isocurves and center curve as profiles. You’ve recreated your inset surface!
18. Extend Surface
Use the Extend Surface command twice, once on each side, with an “Extension Factor” that is large enough to extend the surface past the “V”-shaped curves that represented the original shape of the inset.
19. Pullback "V" Shapes
Run the Pullback command found in the Curves menu to pull back the “V”-shaped curves onto the surface created in Steps 17-18. Repeat for the other side of the surface.
20. Create UV Curves
Start up the Curve menu command Create UV Curves and click on one side of the surface you just created (the side with the “V” shape on it now). During this command, the “Select Curves on Surface to Create UV Curves” prompt appears in the Command line. Select the “V”-shaped curves you “pulled back” onto the surface in Step 19 so these are created flat as well.
21. Copy, Hide, Find Mid.
Duplicate the UV curves using the “InPlace” option in the Command line. Place these on the Gray layer and turn them off, and/or Job Bag them to save a copy for “Flow Along Surface” later in this tutorial!! Now, select the remaining curves, and Explode them. Draw a Line down the midpoint between the long sides of the rectangle as a point of reference.
22. Create a Lattice Design
From the “tip” of the V-shaped curve on one side, draw a Line with the “BothSides” option selected, stopping at the Intersection O-Snap when it hits one side (top or bottom) of the rectangle. Mirror this around to the other side of the UV curves rectangle. Then, Split the top and bottom curves with these two Lines. Using the Divide Curve command on both the top and bottom sides, dividing both of these
into 12 segments each. Point Objects will be added, visually dividing each side. Connect two of these, creating one half of an “X”, and Mirror the half of the “X” around its own midpoint, creating the X. Duplicate the X, using the “Copy from” (one point object) and “Copy to” (the next point object) Command line prompts to assist you. Repeat until the lattice-work pattern – with space for 13 stones – is complete.
Point to copy from, Point to copy to
(above). Finished design (below).
23. Offset, Extend, Trim
Offset each curve, with the “Both Sides” option selected in the Command line, to the width desired for the lattice-work pattern (0.6 on each side, total 1.2 mm, used here). You’ll notice that some of the curves don’t extend to touch the edge of the UV Curves box. After Offsetting them
all, start up the Extend command. The “Boundary” is the edge of the UV Curves box. Click each line that doesn’t reach this box to extend it to touch the curves that represent this box. Run the “Trim” command on all curves, trimming away the parts of the curve that extend past the edges of the UV Curves box. LEAVE the crisscross pattern, but delete the “X” -s inside them.
24. Copy, Hide, Trim
We’re going to use our “Duplicate in place” and “Hide” or Job Bag trick one more time. Select all these curves as-is, Duplicate them with the “InPlace” option selected in the Command line, place them on a layer color you won’t need (and/ or Job Bag them), and turn them off.
Now, select the remaining set of curves and click “Trim”. Click all the curves you won’t need, delete them, and Join the results, till only closed curves remain. Remember: the “V” part of the pattern represents the surface of the ring, so use it to trim the latticework design!
25. Extrude & Extract
Extrude these curves using the Solid menu command Extrude Planar Curves, beneath the original curves, creating a solid block in this shape that is roughly the thickness desired for the top of the ring. Extract the top surface and delete or Hide it, creating an open poly surface.
26. Profiles, Orient 2
Retrieve the curves you duplicated and hid in Step 24. These are your rail curves and will help you create the “Over/Under” effect of the lattice-work design. Create a profile in the shape you want for the top of the ring, using Blend, Rectangle with “Rounded” option (Split half of it away),
or any other method you want. Copy the profile, and select one copy. Turn on its Control Points and click and drag them to create the “Over” (or “Under”, your choice!) profile. Start up Orient 2 Points. The “Reference Points” are the “End” OSnaps of these profiles. The “Target Points” are the Near and Perpendicular OSnaps at the overlap formed by the two sets of rail curves. Orient one – over, for example – then, press Enter to end the command. Orient the other – Under, here –
and end the command. With one “Set” complete, “Copy” this set, using the “Int” O-Snap where the crisscross of the X appears as the “Point to Copy from” and the corresponding Int. O-Snap on the remaining “X”’s as the “Point to Copy to”. Copy this to all parts of the design that follow this particular over/under pattern. Repeat “Orient 2 Points” for both profiles and “Copy” for the next Over/Under part of the pattern. Repeat until all intersections have two profiles!
27. Sweep 2
Your next job is simply to sweep each set of two rails with the profiles that touch it. Use the profiles placed in the previous step. For the ends of each rail, use the “Polysurface Edge” from the poly surface extruded in Step 25 that lines up with the ends of the two rails. For the ends, “Split” one rail with another to create a profile. Repeat until all surfaces are complete. Do NOT join!!
(Above) Split rails with one another to
create profiles at the ends. (Below) After:
(Above) Incidentally, to finish up those pesky little surfaces at the end of each “X”, run the “From Planar Curves” command with the three triangular curves (2 curves and 1 surface edge). (Below) After…
28. Split Surfaces
This is a tricky one, and you’ll use the Layer Color strategy to help you complete it. If you need this to be a closed, solid poly surface (if you don’t, save yourself the headache and skip this step!!), select a surface to split and place it on a layer color you haven’t used yet! Split it with the
surfaces that intersect it. Then, select the surfaces you just used as cutters, and click “Split” to split them with the one they just cut. However, to choose the “Cutter” in this operation, right-click on the layer color on which you place this object, so the “Split” is carried out by all the parts and pieces of this now-split object!! This is a very important step, or else the other
objects won’t be split!! Finally, change the good parts of this surface ONLY – the parts you want to keep – onto a third layer color you haven’t used yet and turn them off. DELETE the tiny parts and pieces that remain!!! If you repeat this, very carefully, with all of the surfaces in the design, everything “good” will end up on the third layer color, open and ready to be Joined to
one another and the extruded bottom of this surface in a closed, solid poly surface when you are done. However, you should check the reverse side of the model for any intersecting surfaces (or leftover little “garbage” surfaces), to check that there are NO intersections before you Join the surfaces. Once you’ve checked, Join them; then, retrieve the extruded surface and Join it to this in a closed solid poly surface.
29. Surfaces for "Flow"
Retrieve the original UV Curves from WAAAAY back in step 21. Explode curves, and sweep a rectangular surface using the two long ends of the rectangle as the rails and the two short ends as the profiles. Click and drag your design up so it sits on top of these two surfaces.
30. Flow Along Surface
Turn on Rhino History and start up the Flow Along Surface command. Select the surface created in Step 30 as the “Base Surface”, and the new, single surface at the top of the ring as the “Target Surface”.
31. Adjust with History
After the “flow” is complete, you may select the flat design and adjust it (click and drag it down into the base surface, or scale it up to be a little larger than the base surface) so that it is in the correct orientation to the rest of the ring and intersects all 3 sides of the inset. The new, curved surface will change, thanks to History. Boolean Union the two.
32. Gem Load > On Srf
Starting in Gem Loader, choose a princesscut stone in the size suitable for the center of the ring. Then, choose the OnSurface OSnap at the bottom of the builder screen. This will open the Gem on the Surface tool, which will prompt you, in the Command line, for a surface onto which to place the gems. Select the single surface that was used in the Flow Command. Now, use the
Builder controls or corresponding shortcut keys to angle and scale the gems where you want them located for the crisscross pattern. Left-click to place each one at the correct size and angle. Complete ¼ of the ring and Mirror to both sides to create a symmetrical design.
33. Gem on Crv > Prongs
Use Extract Isocurve several times, with the Mid O-Snap, to extract a gem line down the center of each “strand” on the over/under pattern. You may use each separate isocurve in a Gem on Curve operation; or, try using Blend between two curves on the same “strand”, and Join all curves in one strand. Input this curve into the Gem on Curve tool. Gem's direction is toward the single surface. While running
In this command, select the “Show Prongs” option from the Command line, and you can adjust both at the same time. Click the “Prong” icon in the builder to jump into this builder if you wish to use the builder controls, and not the handles, to set up the prongs. Each time you add gems to a new isocurve, choose this option and the last used prong style will appear! Complete just one half of the ring and Rotate/Copy gems and prongs to the other half.
Finally.........!!!!
Render it ... looks great ......
Finally, pat yourself on the back: this was
a HARD tutorial!!!!!
S0nt0pku
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