So I am pretty new to Grasshopper, only been at it for a couple of months now, so please forgive my ignorance. I have been stuck on this problem for a couple of days now and just can’t seem to figure it out.
Basically what I am trying to do is recreate an expanding scissor truss structure based on a Chuck Hoberman idea
I have been able to create a singular arc, but am having difficulties now that I am trying to create a unit that I can be arrayed or used to generate a series at varying sizes and orientation.
I believe that the problem that I am experiencing is related to the way in which the data is grouped and matching up data after it has been put through certain components.
Looks very interesting, I’d love to see this when it’s done.
I added a Shift Paths component (yellow group) to get “the radius to relate to the correct arc” and removed ‘Graft’ from the X axis input of that Construct Plane component.
It’s a good idea to disable preview on most components that interfere with a clear picture of your final result, once you understand how earlier components are producing the results you expect. The green ‘preview selected’ button can be very useful for examining intermediate results.
And text panels can be very informative about data tree structures, of course.
Here is basically what I was going for. I would still like to play with the plane of the arc, so that it is not always in the z direction. But that is great, so glad to get it figured out
It was modelled using a polar array of the ‘kinked leg’ bits. It kind of worked. although I probably need to tweak the strengths. If you’re interested in linkages (or anyone reading this), K2 gives an alternative approach in gh that gives a nice understanding of how these systems work - however as above, it would also be nice to know an analytical solution/equation. Maybe the polar array component might help you anyway, as in this definition.
Hidden wires make it difficult to see how it works.
The “scissor action” from moving the “Main Slider” is mysterious to me. Instead of being fixed length, it looks like those segments get longer as the “Main Slider” value approaches zero?
My mistake, I looked at the length of the line segments and they don’t change.
So looking a little deeper, I find myself distracted about the scissor mechanism by several things:
The contortions you go through to manipulate the base points for the arcs. Semi-interesting for their own sake but not related to the method for creating the “scissors” (the part that interests me).
Your base curves are polylines where I expect to find interpolated curves? (minor)
Using lines as radius values. (minor)
Using Relay components, especially when they have only one output. (again, very minor but a personal pet peeve)
Please take these comments with a grain of salt, I’m impressed with your results, even if the scissor “magic” is a little buried in the weeds.