Hi all,
I am currently working on a project where I need to model the hemispherical head of a storage tank made from sheet metal. Unfortunately, Tekla does not support the creation of two inclined surfaces in two planes. As a result, I would like to explore using Grasshopper to achieve this design.
Could you please assist me with getting started on this? Any guidance or resources would be greatly appreciated.
Thank you in advance for your help.
Hi Ah,
Some images or any other information would probably be needed in order to assist you.
But in essence, simply model the hemispherical shape in Rhino either manually or parametrically using Grasshopper. Then use the GH link and push the BREP or MESH in to the Tekla Item component and it will appear in Tekla.
i´d like to help, but do not see the two planes nor inclination
i guess the segments of the head need to be developable?
just did a sketch.
hemsphTankHead.gh (23.9 KB)
Thanks for your help. Sorry how to make this gh script with tekla
i need it like the one in the picture.
variable are raduis and height, segment , diametre , thickness
i can not tell how to run a gh file in tekla if thats the problem.
what was wrong with my gh file and the geometry generated?
please post orthografic sideview of your example geometry. is there a break between the blue and the yellow surfaces?
(you are talking of radius AND diameter? :i guess diameter of cylinder and radius of sphere ?)
Presumably the goal is to detail this so it can be built. How do you roll the shape? I think that will drive the decision on how to model it. Perfectly shaped geometry in the model seems pointless unless you can build it that way.
I asked a Tekla expert we work with in Austria. I am not super skilled in rolled plate. I will let you know what he suggests.
I think the approximate geometry you want is below. That is quite simple using Grasshopper, but I am not sure yet how best to create that in Tekla. I tested lofted plates, but that does not work well for this. I think you need nearly perfect geometry that can be flattened so it can be cut on a CNC. After that it is rolled into the shape and welded. Gaps will be a problem.
It is an interesting problem. The consultant we work with did create a test CC to see if he had a solution. I pasted an image below. I had a follow up question.
I am not done looking at this, but I need to go back to my boring tasks now.
Thanks for your help. That’s the probem that face us all me and my colleagues. i think that tekla doesn’t support a folded part inclined in two plan(tekla cc image). what do you think if we use lofted plate but we revolve to have part like segment (lofts image).
is it a tekla problem?
the geometry can be built , and unrolled in gh / rhino.
Modelling double-curved surfaces as plates is tricky in Tekla. In some cases you can split them up into triangles using the Triangles Generation (19) and Unfold Surface (21) components.
Alternatively, to unroll double-curved surfaces there’s an “Unroll Brep” component in LunchBox. or this C# component from David: Smash command from Rhino - Grasshopper
Those can then be transferred to Tekla as plates and onwards to fabrication. If you have a way to roll them from that.
The more I think about it, I would probably use grasshopper to create the drive geometry. I gather you do this frequently, so a good script can be re-usable. I suspect there is a support structure below the plate, and grasshopper is fantasitc at figuring out the various beam incliniations and setting them in tekla. For the plate work I think I would do that with Rhino and grasshopper. As Sebastian suggests, you can bring the flattened plates into Tekla to maintain the part tracking.
I tested lofts. Lofts are straight from one curve to another. By breaking up the dome into many vertical levels I was able to closely replicate the shape, but the data is virtually useless to create parts you can make.
That CC test was created using polybeams. That results in geometry very similar to what you posted. Polybeams can be flattened, but I don’t think they can be radial in two planes as you require.
Jackob, it is a tekla limitation. Tekla mainly extrudes simple shapes and is not working with exact mathematical geometry. That is not great here, but wonderful for most structural problems since it keeps our models lighter. I have worked with Solidworks, and Revit models. Solidworks can create some fantasitic looking models, but you really need to be careful if the model gets large. They can become very slow to work with.
