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Tweener for Rhino3d - smooth curve interpolation on surfaces with isoline and texture export

Tweener - Probably the most versatile 2d/3d curve tweening toolbox for Rhino and Grasshopper
made by Mathias Fuchs
geometry, graphics, finite elements consulting/programming consulting, programming, project planning Mathias Fuchs, February 2022


Go here to get directly to the example gallery, and downloads.

Why Tweener?

What sets it apart from other Grasshopper assemblies?
Many people use the planar tweening grasshopper components but the actual strength of tweener is to
  • generate "in-between" curves on curved surfaces.
  • the interactive tween editor from the command line interface.
In Rhino without Tweener, there were at least the following existing ways to tween between curves:
  • The in-built TweenCurves command
  • Grasshopper's in-built tweening component.
  • And some other Grasshopper package
However, all of these work with the curves control points, which results in the drawback of a loss of separation between the input and output curves, leading to undesirable undercuts.
In contrast, the Tweener allows to tween between two or more closed curves in a parameter-independent fashion and without overlaps. Thus, the package lends itself specifically to applications such as 3d printing layer design, CNC, landscape architecture etc - typically in landscapes, you don't want overhanging cliffs; likewise a concrete printer usually has difficulties with excessive overhangs. Furthermore, this package provides the unique functionality tween from one outer input curve to two or more inner input curves, instead of just one. Thus, it can generate curves similar to the Cassini curves, for example.
The Tweener is part of a web publishing pipeline for geometrical finite element applications, aiming at enabling both tech-savy and novice users to quickly prototype, and web-deploy parametric finite element applications to general geometric problems, as opposed to just physics applications. Further examples of such applications include image registration, medial axis extraction, Poisson interpolation, and optimal transfer type problems, see here for more info and examples.

What features does the pro license Tweener have and the free one doesn't?

Tweener comes in two flavours: a free license Tweener, and a pro license Tweener. The pro version has the following extras in comparison with the free version:
free version pro version
Number of curves in TweenerExportCurves GH component 5 50
Maximal curve quality in the TweenCurves2 command 9 14
Number of curves in the TweenCurves2 command 10 80
Ability to re-use tween curves in a new Grasshopper component (composing tween operations) no yes

For how long are free and pro versions valid?

From Tweener version 0.3.3891.9201 on, the whole licensing system has been completely overhauled and simplified, to match with my upcoming plugin for heat and insulation simulation.

If you are offline, you only have the functionality of the free license Tweener, and it expires about a week after publication. You might be able get a new week by updating to a new version if there is one.
The week is baked into Tweener - it is counted from the date of publication, not the date of installation. The purpose of this system is to encourage you to stay updated.

If you are online, and don't have a pro license, the free license Tweener is valid for about a week after the date of installation (not the date of publication, as in the offline version.).
If you are online and have a pro license, it will work and will be valid for about a month on as many devices as you like (but you have to get the device names for each device, as explained below.) Each device needs its own activation code.

How do I get a pro Tweener?

For now, it's easy and free as in free beer. Please first update Tweener to the latest version, and then
  • Send me a screenshot of a social media post in which you use Tweener together with a link to https://www.food4rhino.com/en/app/tweener, or
  • Give me a short but insightful description or constructive feedback about how you use or want to use Tweener, with screenshots
Then, run the command Tweener_DeviceName or run the LicenseStatus Grasshopper component, and send me the result to mathias@mathiasfuchs.com. I will send you your license code -- consisting of gibberish 40 characters -- that you can plug into the "TweenerLicense" Grasshopper component.

Tweener help

There is a semi-complete help site here.