Spiral wall

[Scupper]

I'm trying to make a 3D wall shape in V12.5.2 that spirals down at a constant rate in a tightening spiral. I've tried extruding a rectangle around a helix but the rectangle rotates outwards irregularly and I need verticl sides and flat tops.

One way might be to make a spiral, extrude the rectangle around it and lift one end, - but that just lifts one tiny part of it, whether it's a polyline or a NURBS curve.

Any suggestions much appreciated.

Edited October 16, 2007 by Scupper

[islandmon]

Using the RoundWall Tool to create a GoldenPhi Spiral Wall :

1) R=x, sweep =108?

2) Dup Wall>R=x*1.618 >Rot 108?> align edges

3) duplicate and scale per number of turns @ 108?

4) Use 3D Reshape to set the top of each wall segment for alignments.

Note: Make sure all wall base Z=0 and wall thickness is same for all prior to alignments.

See the 4 wall example image attached:

[islandmon]

A few more walls @ 110?, 125?, 90?

see attached images:

[Scupper]

Wow, - that's briliant.

Thanks for taking the time and sharing your knowledge.

[islandmon]

Try this... create a spiral wall & assign a 100% transparency to the side walls and a solid texture to the center.

[Benson Shaw]

Islandmon - pretty cool, as usual. Isn't that series of tangent arcs shape more a volute than a spiral? Or maybe a volute is a type of spiral. I think I can approach a constantly changing radius spiral by using more, shorter segments. Segments about 3' in arc length are probably as close as possible for forming or framing a spiral wall.

Regarding the request for constant slope/height change. Each segment needs to increase in height proportional to its arc length. VW can do the math. Or if the segments are equal arc length, each segment can have same increase.

I tried another way, but got stuck:

Make a truer helix-spiral with the 3d powerpack tool, offset it by desired wall thickness, dupe and flatten both curves, move the helix pair up for initial wall height, then loft the 4 pairs of curves. I got stuck on the off-set - not allowed for hybrids. Also, the spiral tool links the pitch and turns, so after the initial configuration I was unable to change the slope without altering the number of turns. Or is this pilot error?

Anyone have thoughts on this method?

Thanks,

-B

[islandmon]

Create one of these Spiral Wall Towers and then make the sides 100% transparent:

[islandmon]

Come on ... will somebody accept this simple challenge and post a rendering of it with side walls=100% transparency and the center of the wall a solid texture ...

I dare you ... double and triple dare you ...

[Pat Stanford]

Island Mon,

You mean like this? All three wall sections have glass texture left and right. Center is Concrete.

Interesting that you can see the other walls through the transparent wall, but not the cylinders.

Pat

?

[mike m oz]

Different wall and different result for me.

[islandmon]

This points to new functionality for the RoundWall Tool...the solution of the "flat spiral" problem. If we could assign a profile then we could use this tool to create the elusive Wall Cap ... thus avoiding the Helix Dihedral twisting issue of ExtrudeAlongPath:

[Petri]

About spirals:

http://en.wikipedia.org/wiki/Image:Confusion_of_Tongues.png

[Benson Shaw]

I worked it out another way. Roundwalls are convienent here, and probably waaay quicker, but the series of tangent arcs is not same shape as spiral with constantly changing radius. Also, raising each section end for constant slope is a bit of a pain. This solution is more involved, but does give a way to get constant slope and constant radius change. Can be adapted to any wall shape with varying heights. I also tried to use the spiral poly in a Convert Poly to Landscape Wall operation. The result was strange.

Examples from my process:

http://www.bensonshaw.com/bensonshaw.com/SpiralWallFRW.html

http://www.bensonshaw.com/bensonshaw.com/SpiralWallWF.html

(how does one represent these long urls with shorter, descriptive text?)

Create 4 Nurbes curves. Two on ground plane. Two others rising above them. Create Surfaces from the various pairs of curves and Compose to make the wall. Here is my blow by blow:

1. Use the 2D spiral tool to make a spiral which is wall center line.

2. Create a 3d line segment with length equal to wall width.

3. Duplicate Along Path -tangent - choose number of dupes or spacing increment. Larger number of dupes gives more exact curve (I used 20 dupes on a 20' spiral).

4. Group the dupes color them Red. Duplicate In Place. Color the DupeGroup Green.

5. Enter Red Group and create two nurbs curves connecting the end points of the 3d segments. Nurbs #1 connects the inside end points. Nurbs #2 connects the outside.

This is the ground plane Nurbs pair - Bottom of Wall shape.

6. Exit Red and Enter Green. Move the whole group up to height at lower end of wall (eg 1 meter)

7. Select each of the 3d segments in turn, and change its z value. Add an increment "h" to the total z of the previous segment: Z of N2 = Z of N1 + h (Sorry, no subscripts for the progression formula)

8. Connect the end points of these raised segments with two more Nurbs curves. These are the edges of the Top of Wall.

9. Isolate the 4 Nurbs in their own group and enter it so the centerline and tangent segments are not visible.

10. Make your wall: Connect the end points of the pairs with straight (2 verticies) Nurbs curves and apply Create Surface from Curves. Red to red gives bottom of wall - Use the Create Surface from Curves in 3d PowerPack. Green to green makes the wall top. Dupe or extract curves to get two more pairs. Red to green gives the wall sides. Create Surfaces from Curves. Extract edges to make the end caps.

Compose all or some surfaces for texture combos, area/volume and other info.

-B

[islandmon]

Very excellent work ... primo recipe for others to follow when baking this cake ; )

the series of tangent arcs is not same shape as spiral with constantly changing radius.

Yeah ... the GoldenSpiral made from RoundWalls is not a true Logarithmic Spiral but good enough for most field applications where constant radii from fixed GoldenRectangle points are easier to measure than constantly changing radii.

(how does one represent these long urls with shorter, descriptive text?)

Must use the New Reply at TOP of Page and then use the URL button and/or just add the files via the File Manager

[Petri]

Yeah ... the GoldenSpiral made from RoundWalls is not a true Logarithmic Spiral but good enough for most field applications where constant radii from fixed GoldenRectangle points are easier to measure than constantly changing radii.

In Awstraya they'd use a stick and a length of string. They're very handy with string and sticks there.

[Petri]

Also, raising each section end for constant slope is a bit of a pain.

Scriptable.

[islandmon]

Actually, only the first segment needs to be set up for arc-radius-slope.

Subsequent> duplicate>scale>rotate by segment angle ... and set into end-to-end. Each larger segment nests perfectly with the previous smaller one. No additional slope adjustments are required.