Help needed with circular beams and 'free-form' shape.

[Anonymous]

Hello,

So I'm trying to create a steel structure (concept) that can be bent on plan (so it's basically stretchable)

A precedent to what I'm trying to create can be found here: Image

I've used OBJECTiVE for a less complicated form but it needs developing. I can't seem to find a way of altering the shape in plan whilst also retaining it's vertical height etc.

I've attached what I have already achieved, by using the regular profile and OBJECTiVE, but all the arcs need to be joined together (and the from needs changing) (Also, my file is extremely slow since placing these arcs, is there a way to speed it up?)

As you can see from the attachment below, in plan the existing arcs are straight lines at various angles. I want to be able to bend the profile in plan. (the height of each curve can be determined in elevation).

[/img]Exsisting Plan


The beam and magic want do not work unfortunately. The profile needs to be able to "stretch"... I should also add that the total length of this singular piece of steel will be around 80 metres. (though I can cut it and join it together if there is a limit in terms of length.)


Image

Thank You very much, Hopefully such a task can be carried out... ArchiCAD 15 looks like it can do this but my deadline is next week!

[Steve Jepson]

Thanks for sharing your project. I think it's cool.
As for how to make those pipes. Hmm...
That will be a bit of a challenge. Especially if it needs to be dimensionable, manufacturable, and constructible. I hope you will post the solution.

I have in mind a few things I will try but I don't expect to be able to do it very well.

Have you tried using the Spiral object in the Basic Shapes library folder?

This was easy using complex profile and some spirals of same dia.

[Anonymous]

Thanks for your post,

I've looked at the spiral and whilst it has the correct 'form' for my concept, it isn't flexible enough i.e it will always keep the same ratio or curve. Also it doesn't seem to be editable in plan.

I'm going to keep trying things, but I think that I will end up taking it to Cinema4D, then back into ArchiCAD if that's even possible. I know exactly how to do this in C4D but I get the feeling that things such as this drawn in C4D are too 'sloppy' or don't look solid like they would in ArchiCAD.

Thanks again.

[Anonymous]

You can try 3D Tubing object in the library below (Tubes folder).

Follow insrtructions, and you will be able to do any path for a tube, in 3D window.
Work in wireframe mode with the lowest resolution (4), and check 3D Axis On.
A resolution of 12 is good enough for a rendering and a decent Polycount.

[Ralph Wessel]

NStocks wrote:
So I'm trying to create a steel structure (concept) that can be bent on plan (so it's basically stretchable)
I've used OBJECTiVE for a less complicated form but it needs developing. I can't seem to find a way of altering the shape in plan whilst also retaining it's vertical height etc.

You should be able to do this relatively easily with OBJECTiVE (if I understand your requirements correctly). I assume that once you have the correct curve in elevation, you want to further deform the shape in plan to form something like a spiral? If so, take a look at the attached image:

• 1. Place the profiled object in elevation and use OBJECTiVE > Tools > Bend to bend it to the required height.
  
  2. The resulting curve in elevation.
  
  3. Here is the key step for you. Viewing the object in plan, I can reshape the object (without changing the curve height) by using OBJECTiVE > Tools > Offset, and stretching the end to the required position.
  
  4. The result in plan.
  
  5. The result in elevation
  
  6. The result in 3D
  
  7. Several objects can then be linked into a spiral as required.
  
  8. You can speed up the object display by increasing the Faceting value in the OBJECTiVE settings dialog.This is a tolerance setting, i.e. how far the facetted shape can deviate from the true curve. The higher you make this value, the fewer faces there will be in your 3D model and the faster is will display. The tradeoff is that the object will appear progressively less smooth, but it's surprising how good it can look with high tolerances.

This technique will also work with all the steel profiles bundled with OBJECTiVE.

[Anonymous]

Thank you Olivier and Ralph for your suggestions.

Ralph, I want to be able to freely move the points on plan, rather than just offsetting them. I don't have a image of why I want exactly yet because I'm still referencing nodes to create such a form.

I've just tested the Offset and found that it moves in a fixed position. I want to be able to move it in any position... Again, the nodes are not yet established, but it's more than likely that I will need more free movement on plan. (it's in no way a symmetrical form)

Another precedent: Armani Store

EDIT: Ideally I'd like to keep the whole structure as one piece (so around 120 metres long) would it be possible to add more nodes/hotspots to create more curves but retain curves already created? I know I'm asking a lot!)

[Ralph Wessel]

NStocks wrote:
I've just tested the Offset and found that it moves in a fixed position. I want to be able to move it in any position...EDIT: Ideally I'd like to keep the whole structure as one piece (so around 120 metres long) would it be possible to add more nodes/hotspots to create more curves but retain curves already created?

You'll find that although 'Offset' stretches in one axis, you can still stretch in the other axis simply by clicking and stretching the hotspot at either end. The combination of offset and stretching can move the endpoints anywhere you like.

Note also that you can bend and offset in 2 different axes simultaneously. Combining that with the twisting parameters can create some very convoluted shapes if required. The attached image provides an example similar to the image you linked to.

OBJECTiVE will not allow you to create a multi-node 3D spline. You would need to break the shape down into segments to make more complex paths.

[Ralph Wessel]

NStocks wrote:
Ideally I'd like to keep the whole structure as one piece (so around 120 metres long) would it be possible to add more nodes/hotspots to create more curves but retain curves already created?

The attached image shows a series of segments modelled with OBJECTiVE to form a continuous strip.

[Anonymous]

Ralph wrote:

NStocks wrote:
Ideally I'd like to keep the whole structure as one piece (so around 120 metres long) would it be possible to add more nodes/hotspots to create more curves but retain curves already created?

The attached image shows a series of segments modelled with OBJECTiVE to form a continuous strip.

That image has convinced me to use OBJECTiVE for this task! (i've used OBJECTiVE on every project since starting University , I didn't think it would be easy or fast enough to use OBJECTiVE in this case, however I was wrong!)

How did you get each piece to join up so neatly? Would it be just as easy to join a circular profile?

I will post my design tomorrow evening hopefully,

P.S How long is the continuos strip that was previously posted?

Thank you so much.

[Anonymous]

Here's one I just created, using an existing arc.

Admittedly it was a random move but that's not always a bad thing! I think this project is too free-form to calculate accurate measurements the first time round, so I'll just use poly lines etc. as a reference guide.