Need help about using Kangaroo for form finding

Dear all the experts in Kangaroo,

I newly learned to use Kangaroo to do form finding.

However, the tutorial is not clear and I met an error in my practice.

The .3dm and .gh documents are attached. Can anyone help me to solve this error?

Much thanks,

Xue Zhengyu

Attachments:

error document.gh, 19 KB
error.3dm, 73 KB

Replies to This Discussion

Permalink Reply by peter fotiadis on May 18, 2016 at 11:43am

Dear NaturallyBornKillerButNotYetQuiteThere.

1. You are already like me (with regard the basics) > the only thing MIA is the ruthless training > the easy bit.

2. WHAT is this spaghetti chaos? Are we here to eat pasta or kill them all? That's the big philosophical question of the day.

3. Struts that are smallish (I.e the part "engulfed" by the top/bottom cables) they can't support the long ones (their "continuation"/extension towards the roof, that is) unless (a) they are fat (and ugly) as my mother in law (b) they are proper AND supported by cables: for each top pt (on roof level) connect with the north/south/east/west points that belong to the top tensegrity grid. You'll see what I mean rather soon. This is the reason that the strut is a 2 parts combo (in order to allow some "oops" moments at assembly time - the norm, that is).

4. That way (BTW: Adios "neatness" welcome real-life) the long struts are requested to sustain axial compression forces (yielding no bending torque) whilst the @$%$@ cables do what cables do (tension forces).

BTW: These cables have nothing to do with the ones used for the T truss system.

5. But whilst all the above are rather obvious ... the thing that IS NOT is what is actually required on the roof level in order to allow the real-life alignment ("planarization") of the roof panels. But if we combine that "mini beam grid" (see Jansen-Viss hybrid facade/roof systems) with proper planar glazing "ultra cheapo" (kinda) SS 306 brackets (not to be confused with structural glazing, mind) > yes > that could cut the mustard properly (I.M.Pei do you agree?).

That said the ONLY way to get rid of stationary pockets of dirty rain water (in min slope roofs) is a planar glazing system - other wise the whole thingy is kinda the 3rd marriage.

More soon

Permalink Reply by peter fotiadis on May 19, 2016 at 9:47am

Restart + Reset from node 0.

I was ready to deliver the 4 C# combo and the connection 3d thingies (from CATIA) ... but then I said: what the hell > let's make some ultra complex solution that costs 3 arms and 6 legs (PS: Remember: in real-life our fee is proportional to the budget > thus > like Godzilla > the bigger the better).

In the mean time (auto detection of struts < min Allowed == true) get the gist of the whole "torque" issue, the other gist not to mention the other-other gist.

Of course you can opt for NOT making the cables (green) that stabilize the "extension" part of a given tensegrity strut ... yielding the Mother in Law syndrome (fat and ugly):

But ... hmm ... well ... are you really the chosen one? Here's your chance for the ticket to Paradise (full Lord's assistance, that is). Identify this engine, name the designer and the related immortal racer (when men were men).

Moral: Heaven can wait.

Permalink Reply by Igor Mitrić Lavovski on May 19, 2016 at 10:42am

Porsche motor, designer = F.Porsche, racer Dean James :)

Permalink Reply by Zhengyu Xue on May 19, 2016 at 11:17am

Ha, maybe you'll get the pass to Paradise.

Good luck!

Permalink Reply by peter fotiadis on May 20, 2016 at 1:22am

In fact for real Paradise you'll need the multipass as well:

BTW: Drafts for your case: planar glazing + an alignment mini square tubes grid (that could host cool poly carbonate shading fins) + bespoke ball pivot joints for the extension strut (keep an eye on class situations) + a zillion of other nuts and bits not shown.

These mini squares could be part of a classic Jansen-Viss hybrid glazing (the internal part == steel, the external aluminum + plastic thermal bridges connectors) in case that the planer system is too expensive (1K++/m2).

Ball pivot joins are widely used elsewhere as well (for obvious reasons).

If Tensegrity struts are smallish (see the red spheres in the previous shots) then ... er are treated rather as "spacers" than actual struts. Of course their "extensions" are always struts since the length is sufficient to justify a strut.

Permalink Reply by peter fotiadis on May 19, 2016 at 11:23am

917 Flat 12 boxer motor (at CAN-AM turbocharged), designer chief engineer Hans Mezger under the leadership of Ferdinand Piëch and Helmuth Bott, propelling the most iconic endurance racer of all times (BUT NOT the most successful).

Racers: too many to mention (Ickx, Bell, ...) and (virtually) a certain Steve McQueen

Permalink Reply by Zhengyu Xue on May 19, 2016 at 11:14am

Dear LordWithPorscheFerrariLamborghini,

I completely believe that you have more hands than the Buddhist..

Thanks for the hint from Mr. Igor, I found a website with the engine blueprint for porsche-917

http://tech-racingcars.wikidot.com/porsche-917. Apparently there is another gazillion about cars..

B.T.W, because I've never been to the paradise, all I can do is to enjoy this suffering: Different shit everyday convinces me I am progressing.

Best,

TheManIsNoOne

Permalink Reply by peter fotiadis on May 20, 2016 at 5:24am

Here comes the pain (tears/agony optional):

1. This is an approved by The Lord (Himself) "linkage" solution that works in any situation ... I mean it could work IF you were able to design parametric parts AND "fit" them to a parametric topology (or the other thing) made by these #$#%$ C# (or 1M native components).

The original (CATIA + Microstation > feature driven parts + dimension driven design (a what?) + some spiritual help by means of a proper Stoli Elite (a must)):

Since tensegrity struts "meet" the upper and lower cable grid at different angles (AND the roof grid) ... welll ... the ball pivot thingy is a must: deals with similar freaky situations.

The pathetic translation to Rhino (all intelligence lost, all the assembly component info lost, plus my cat is MIA as well):

2. It's rather obvious that solving a "mechanism" of that type with FEA ... well ... what exactly you intent to check? (Remember what I said months ago on that matter?).

3. Placing some of these in some Rhino file requires dealing exclusively with instance definitions (only doable via code for that level of complexity).

4. If your tutors find this "complex" > chance tutors. BTW: NEVER use one cable that "cross" the members in question > Armageddon > adios Amigos.

Moral: long is the path and hilly (not to mention that there's no path around).

best, Lord of Darkness, Prince of SardineLand.

Attachments:

272_China_EC2_tensegrity.stp, 4.5 MB

Permalink Reply by peter fotiadis on May 20, 2016 at 5:30am

And here's a 3DPDF that "retains" (not exactly ... but kinda) the reference structure (exported from Microstation).

Use the Latest Reader + Model Tree (in order to isolate things) and/or Sections. DO NOT load this with Reader as client to some browser (you'll see nothing).

Attachments:

272_China_EC2_tensegrity-Master-000.pdf, 574 KB

Permalink Reply by Zhengyu Xue on May 20, 2016 at 7:24am

Best LordofKepler,

I remember you once sent me the 3d pdf file of similar connection and I indeed considered about it(possible to draw a similar connection in a parametric way).

Thus the conclusion is that I need to make a choice between the below 2:

1) Use cable segments between struts + the same connector for cable and strut (from your design)

2) Use continuous cables + different connector

Er,, I choose cable rather than rod as the element for tensegrity with an intention that cable can be continuous, and for cable the ratio of (breaking load)/(section area) is much higher than the strength of rod(eg S355). Thus less material (but , also the stiffness of cable could be less than half as that of rod due to smaller cross section and smaller Elastic modulus).So I want to know between cable and rod, which one would you like to use?

Best,

Le Petit Prince van B512

Permalink Reply by peter fotiadis on May 20, 2016 at 8:30am

First things first:

1.NEVER use continuous cables for such kind of stuff: it's Academic and out of question since it's impossible to hold the cable in place with these joke like bolts. Additionally assembling the T truss that way it could be a nightmare. Additionally this requires a different "cyan" member per top/bottom node > are we talking projects here or some hallucination due to Tequila overdose? (You tell me).

And if using this continuous awful thingy ... who could tell when exactly the strut direction is the right one? Are we talking stuff here or "stuff"?

2. NEVER mix the relative accuracy (T truss) with the absolute accuracy (some planar glazing system). It's Academic ... blah, blah. In plan English: a strut that "continues" up to the sky to meet the roof grid it's out of question not only due to accuracy reasons but also for torque reasons as well.

For instance: an assembly error of, say, 5 mm (the norm) in the top cable net it would be several centimeters at roof level (for obvious reasons). Moral: NEVER ever do that. It doesn't matter that this is Academic > bad/wrong habits die last.

3. Cable based stuff means: USE as much cables as you dare in order to have piece in mind.

PS: If tutors guided you towards a continuous cable solution > replace tutors. If that was due to Tequila > swap with Vodka.

best, Lord of Darkness (aka: The Merciless)

Permalink Reply by peter fotiadis on May 20, 2016 at 10:05am

Lesson of the day:

The obvious fact that you can't design such stuff parametrically (as GH can apply the term and as R can do) is NOT an excuse to use Pink Planet stuff/solutions.

If you are after similar real-life AEC things that in fact are complex assemblies ... then your next (actually the first) step should be top-dog MCAD apps (but try Microstation + Generative components as well).

But given the opportunity there's 2 kind of "parametric" things out there:

1. The Topology (an abstract collection mostly of coordinate systems) that can been handled via graphical editors like GH. If there's some logic behind ... then ... maybe ... we can talk about algorithmic stuff (but who cares about names? not me anyway).

2. The real-life 3d things that are designed via dimension driven design, history based modeling, feature modelling etc etc (using exclusively high end solid modeling apps NOT surface modellers like Rhino). Basically you design these "by hand" (by mouse in fact) and then you "export" their "events" that "matter" to the app that does the 1 > then either you change them (clash/cost/structural/aesthetic reasons etc) or you change the topology. If these are ready parts from the market (kinda like the Norsman cable tensioners used) then ... you just keep them in RDBMS controlled repositories and use them accordingly. But if the project is really bespoke you can design them too as well (blame client's vanity).

So you have 2 kinds of "parametric": the theory and the reality ... whilst the "ideal" solution is some kind of equilibrium between "I want" and "I can".

On the other hand doing FEA on real-life bespoke complex parts ... well .... as I said months ago > what about some other Project? he, he.

But ... hope dies last ... there's a "middle" solution as well: wait for the 4 horsemen (the 4 C# that in fact are 5).

You'll be surprised