Grasshopper Dome

[zvgQhAoJ]

I have been trying to remake this dome on grasshopper, but I haven’t been able to find any tutorials or examples of how to make one that look like it.

I am mostly struggling with getting the shape of dome right, can anyone help me with an example or some information?

Thank you.

[Eef_Weenink]

Dear Emilya,

Please upload what you already did, that will help advising you.
For now, looking at the shapes, I would start like this:

• In the bottom image, the top curves seem to be made of two arches (very large radius).
  where they meet, there is a fillet in the curve. Let’s call this the topline
  So I would play with circles, attached to that meeting point, and find a system with sliders to change radii and positions of the origins of the circles.
• In the top image there seems to a simular arch/circle with less deep radius.
• The topline curve is rotated several times to left + right.
• combining both will give you a drop-like shape.
• The dome is a section of that.

PS: The image below is made in another way:

• Split sphere in parts, scale parts, join them and split of a section
  
  

Regards, Eef

[zvgQhAoJ]

Thanks for your suggestions! I’ve started with an ellipsoid as my base, but I’m having trouble getting the dome shape right. I’ve tried cutting and connecting the ellipsoid with curves, but it didn’t work as expected.

I think I might be approaching the shape incorrectly. Do you think starting with the ellipsoid and slicing it to create the dome would be a good approach, or should I try using your method of creating arches and rotating them? I’m still trying to figure out how to get the curves right to create the top part of the dome.

Would love your thoughts on this approach, and if you have any suggestions for the next steps to refine the shape further, that would be great!

Thanks again!

[Eef_Weenink]

You could start with anything and shape it untill it fits. but will take long time to get there.

I would centainly not start with an ellips (and also the trial I did with scale 1/2 spheres is not easy to control.
I see arches /circles. I would try to find there centre + raddi and create curves from

I marked what I see whith green + red. The green have there centre deep in the earth, the red are more fillets.
Maybe in the end they are not eactly circles, but that is more easy to adjust.

• Start with the two toplines.
• creates planes (angled)
• use tween curves + orient to get them the size and place you want.

Just give it a try, upload what you get, and you get a lot of help on the forum.
Regards, Eef

[luisbarthelemy]

Hey there!

I think the elipsoids are a not a bad approach, even though in the end the shape is not based on an elipsis I believe. The two domes are like UFOs half sunk into the earth and to me it seems like the entire geometry is following that master shape, but the corner is too sharp for a real elipsis. But it definitely looks like a rotational body to me.

I am not as experienced with GH as many in this forum so there might be a smarter way to do this, but I would say create that curve first and make a rotational solid out of it. Somewhat easy way would be a NURBS Curve where you put some points and move until it looks right. This you can also try outside Grasshopper to get a general feel for it.

Play around with the parameters until you find the shape you want. This you can revolve into your master surface. You can then also offset the curve to get the outer beams in your example. Then orient/rotate it and put a big box from down which you use to cut the lower part, until the UFO is sunken to the right extent…

In your example, it seems like not everything is perfectly aligned with these master shapes, especially the outer beams are deviating (on the top image). This will be more complicated to do. And well, generally with all parametric design the general shape is one thing, getting a buildable construction out of is a fully different story….

Good luck!

Edit: Ah yes I just saw Eefs reply, he’s basically saying the same thing just somewhat more elaborate

[Eef_Weenink]

Sections of two circles + fillet.

[zvgQhAoJ]

Hey Eef,

Thank you so much for your help.

I am struggling a little with creating curves in Grasshopper. Is there a way to create the curves of the dome in Grasshopper without having to draw anything in Rhino?

Thanks, Emilya.

[Eef_Weenink]

Yes, it is possible.
That is what I did in the example. I started with the CONSTRUCT POINT
and then made a circle there,

So please upload what you have done so far. Upload the .3dm file + .gh file and you will get a lot of help here. We want to help you, to do it yourself and learn. We will upload code when you do. Regards, Eef

[zvgQhAoJ]

Hey,

I am sorry for the late response. I have been really busy the past week; I haven’t been able to work on this yet.

I uploaded what I originally had from last week. I would appreciate any help to fix the shape to make it look more like the actual dome.

Best, Emilya.

Dome.gh (24.5 KB)

Domw.3dm (41.9 KB)

[Eef_Weenink]

Dear Emilya,

I do not have the time to do it all the way, but let’s give it a good start.

1. I made a curve, completely composed with sections of circles. Study, how I use these to move the center point around, change the radius, and sections cutoff.
   1a. To keep those two together, I used the connection-point between the two halve curves as starting point. You can easily “move” the object later with Orient to any plane you want.
   1b. To finish the curve off I added a fillet. And a slider to change the heigth.
   This way you have 6 sliders to fine tune the curve as you want

2. The curve perpendicular is (I think) also an arc. It looks symmetric so you just need a small part of the group components needed for the 1st curve. I would start with the point at the top again. Circle on the other plane downward. and circle back (as I did with the first curve). Also cut off a. the same section.

3. Use this section as the rail for Rail Revolution

Open the file and look (circle around) in preview, to see how it works in 3D

marina bay domesEW1.gh (37.5 KB)