Tuesday, October 23, 2012


How to make a spring onion for a wig hat  ...  AKA  ... the general instructions for making an adaptive scaleable rig.

Place 2 points, one vertically above the other & make them adaptive.  Spline by points, make reference.  Set current work plane to back/front of one of the points, place another point, give it an offset.  Repeat for the other point.  Join it all up into a rectangle, make all lines references.


Let's call the original ref line joining the 2 adaptive points the "Backbone".  Set current plane to L/R of backbone.  Dimension between the adaptive points.  Make it a reporting parameter "H".

 Parameterise the offset value of the other 2 points, let's call it "D" for depth.  And we'll set up a simple relationship between Depth & Height based on a factor "F".  This basic rig can be used for almost anything.  Place points to give the curves you want.  Actually the curves shown here are from a first failed attempt.  Had to simplify second time around

Prepare a profile for scaling.  The idea here is that the radius of each instance along the path can be easily adjusted.  Just select the profile and type in a new "input" value.  Meanwhile there is a master "scale" factor which is linked to "H" in the host family.  So move the adaptive points apart and all the profiles adjust proportionally.

The profile goes on to the curves, repeatedly.  For the spring onion I needed about 10 strung along 2 paths. 

It's a stylised sprint onion, one white section that bulges out, 2 green legs emerging with constant radius.  This is complex enough without getting carried away.

The width factor (F) serves to vary the curvaciousness.

The first repeater was based on simple circular arcs, drawn on horizontal planes.  Had to set the adaptive points to "orthogonal in family" in order to avert a bout of wonkiness.


Second iteration of divide & repeat used 2 tiers of dancing green onions.  I like these little guys.

third time around I went for free-flowing splines and eventually 3 tiers.  We need to evoke the raggety locks of a wicked witch.

Now we have a wig hat, (reference to "high heeled sneakers", the music to this post is pure class, Tommy Tucker & Booker T ) so now we have a wig hat I can bring back the face.  I am making the whole head into a sub-assembly so it's easier to cock to one side in the main model.  Going after that sneaky sideways look mentioned in a previous post.  Trying hard to name my families sensibly also.
I think the butternut squash chin is a nifty move.  Tasty too.

By the way I discovered something very handy while building my spring onions.  It's an extension to the previous revelation that you can select a spline, select a point or 2 & create form to extend the line without the trouble of re-building.  Sometimes it's the only way to get points to join up in the order you want.  WELL you can do the same with forms.  Select a form based on 3 or 4 profiles, select more profiles & create form.  The lofted form will extend.  This is magic.  You made something with 7 profiles only to realise you need another 2 to get the bulges you desire.  No need to dissolve it all and start again, re-apply material parameters etc.  Is this documented anywhere ?


  1. Andy, you're awesome...
    I keep kinding myself at your BLOG,
    I hope to meet you someday...

    1. My name is Adam Munoz by the way, I curently live in Roseville, California.

  2. Thanks Adam
    Never been to California but one of my sons spent an academic year there ... must be 3 years ago now. Have a daughter in New York so I've been there twice.


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