Geodesic Dome Truss by TaffGoch - cloning to sphere?

[Tonttu]

Geodesic Dome Truss
TaffGoch says in the description: "Can be used to construct geodesic dome or sphere"
I'm actually a total SketchUp newbie, coming from Lightwave and I was wondering if SketchUp has a feature to construct a truss sphere by cloning from this "triangle" model of TaffGoch? Manual rotation and placement is a bit tedious

[Pilou]

maybe something like that
(I have made a zoom on the triangle)

truss.jpg

the module = one component
Reverse faces of the sphere
and use this plug by Chris Fullmer
Components onto face

[Tonttu]

Thanks Frenchy. The dome truss by TaffGoch has a honeycomb as the bottom shape, though, and not a triangle.

[Dave R]

The outsides are triangles, though so it shouldn't matter.

[TaffGoch]

 
Tonttu,

I don't think that Frenchy's suggestion will work (unless Chris Fulmer modified his plugin, to autorotate & scale-to-fit.)

That particular truss will only produce a sphere if 20 copies are used, rotated around the correct axes, by the correct angles. I did exactly that, in less than a minute:

IcosaTrusses.png

The angles are not troublesome (72°), but the axis-of-rotation might cause a SketchUp novice some problems.

Do you already know how to rotate entities around any axis of choice?

SketchUp permits you to select the endpoints of the rotate axis-line. ( SketchUp Sage - Rotate Tool )

Using the Sketchup "any axis" technique, choose the origin as one endpoint, and a corner of the truss as the other end. A 72° rotation will butt the edges of the two trusses against each other. (Beforehand, you should make that truss a group or component, to make selection easier.)

-Taff

[Tonttu]

Many thanks for the mini-tutorial! Yes, I'm a complete novice, but I'm familiar with action centers/axes especially from working with Modo, so I think I can get the hang of those any axis rotations.

[Pilou]

@TaffGoch : you rocks
I have seen your origin or rotation in the first file linked
I had the intuition that your part of truss can make a sphere but want to find another method

I believe that the Chris Fullmer plug can make the trick (inside a geodesic Sphere)but you must adjust the module component position after running the plug
if you have made the module without attention
It's the internal axe of the module component who makes the différence!
(so edit the module component

You have also somme plugins like Mirror by Tig or Align by Didier Bur who can help for make somme copies in the space
when they are not align to the axes

[Tonttu]

How do I find the origin (0,0,0 ?) for the rotation? The truss was already a component, so I copied and pasted it in place.

[gilles]

zoom out the model you will find a guide point it's the center of the geode

[Tonttu]

Yeah I tried that center point already (at the bottom), but using it as the first point and a corner as the endpoint only gave me a "six pointed star", ie. it rotated around the center point.

[Tonttu]

Ok I chose the points in reverse order and it seemed to do a better job, but it's a long way from a curved surface! This is basically a radial array, which will just produce a bumpy result.

[TaffGoch]

Tonttu,

If you have guides visible (View > Guides),  you should see the central guidepoint.

Use
 (1) that guidepoint and
 (2) one of the primary corners of the truss, as
 (3) the endpoints of the rotation axis,
 (4) rotate by 72°

IcosaTruss_2.png

I have revised the model to show, more-clearly, the rotation axes. (The guidepoint was already there. I added only the guidelines.)

-Taff

[TaffGoch]

 
Tonttu,

I see now what you're doing wrong!

You are not using the "drag" technique, to specify the endpoints of the rotation axis.

You are, wrongly, rotating in some other plane; perhaps, the "blue" plane.

-Taff

[Tonttu]

Ok I changed to women's clothing and I'm trying to rotate now.. Kidding! Thanks man, you've opened a new psychedelic world of rotation for me! Everything is locking into place now.

[TaffGoch]

Tonttu,

You can understand why I always teach that rotation technique first, to a new user.

I couldn't model without it!

[jim4366]

For me, it seems to depend on which of the 3 axes I pick. If I rotate on AB or AC, the edges don't exactly align. You have to zoom in a lot though to see it. It's easier to see if you rotate/copy the construction lines too. Rotating on AD though works.
Is this right???

Capture1.jpg

Edit:
Actually I don't think AD aligns either.
Don't know how I came to that conclusion.

[Tonttu]

Yes I noticed the slight misalignments, but I think the accuracy is enough for my purposes.

[TaffGoch]

 
My apologies,

This is one of my oldest SketchUp models, which I built while learning SketchUp. As such, there are slight inaccuracies, regarding alignment of the groups and guidepoints. So, your rotation alignment problems were caused by my inaccuracies in placing the central guidepoints.

I have updated the model, to properly-align. I have also included an icosahedron, to depict and help visualize the rotation symmetries. I rotated the truss component, to the more-prevalent orientation, of a primary vertex pointing upwards (rather than a face.)

Update in 3D Warehouse: Geodesic Dome Truss

-Taff

[jim4366]

Hey no problem. To see it snap into place...
It's a thing of joy and beauty.
Thank you so much.

[brookefox]

@TaffGoch : you rocks
I believe that the Chris Fullmer plug can make the trick (inside a geodesic Sphere)but you must adjust the module component position after running the plug
if you have made the module without attention
It's the internal axe of the module component who makes the différence!
(so edit the module component

It would seem that you are correct, professor, and I had some success at relocating the component axes for the purpose of using the component on to face plugin to exactly place the 20 pieces, but not nearly good enough.

Did you ever figure it?

geodesic-compo to face-1.JPG

geodesic-compo to face-2.JPG

geodesic-compo to face-3.JPG

[brookefox]

'Component onto face' doesn't know the rotation that is desired and so cannot necessarily properly rotate it but still it can be used and the results tweaked because in this case there are only 2 rotations.

pic shows components as placed; 10 'wrong', 10 'right.' All endpoints should be at intersections.

faces into components-2.JPG

pic shows 10 'wrong' rotated internally and redefined. So job is done with 2 rather than 1 component definition.

faces into components-3.JPG

faces into components-4.JPG

[pbacot]

What if you turned it over then applied the same component definition?

[brookefox]

I don't think so but I'm perhaps not sure what you mean.