Creating Hemisphere without any extraordinary point at the bottom

Rhino Rhino for Windows
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Hello everyone,

I am very new to Rhino so kindly accept my apology in advance if I am being very naive in the following.

I need to construct a hemisphere (as shown in the attached image) for my assignment work. WIth the default/standard features in rhino, I could construct only the full sphere which intrinsically comes with the two extraordinary points (at the top and bottom). But, such points in the sphere mesh are not desirable in my case.

Therefore, I was hoping for some help from you guys in constructing something similar to one shown in the attached image. Thank you so much.

Best,
Vishal

hemi-sphere
hemi-sphere743×483 13.7 KB

PS: At the bottom centre, the final construction could look like this (image attached, please ignore the colors in the image).
final

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Is this what you’re looking for?

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Thank you @Mahdiyar for your response.

That post includes the construction of a full sphere using six patches. With that approach, I agree that a sphere can be created without having any extraordinary points.

But, here, I am looking for the creation procedure of a hemisphere. I am not sure if I can construct the hemisphere using the similar six patch approach.

4

Hi,
You’re looking something similar like this

hemi
hemi935×457 24 KB

Cheers,
BVR

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5

Thank you @ajarindia for your response.

Yes, I am looking for something similar to this.

Generating the mesh in the bulk is not a focus here. Just the hemisphere (even the hollow one) would be fine as long as it doesn’t have any extraordinary point at the bottom while using more elements at the surface (as shown in the attached image of my first post).

I will be happy if you could describe the construction procedure.

6

Hi

Check this video

no guarantee on this

2 Likes
7

Thanks for this.

But, even with this way, I get an extraordinary point at the bottom of the hemisphere (a common junction points for the mesh wires used to construct the sphere). This one will end something like this (see attached image), which is not desirable.

ErrorMsg-Rhino
ErrorMsg-Rhino1270×787 90.6 KB

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2020-06-06 12_54_49-Rhinoceros 6 Commercial- - Perspective
2020-06-06 12_54_49-Rhinoceros 6 Commercial- - Perspective1280×609 94.6 KB
semi sphere.gh (7.3 KB)

maybe this can help.

2 Likes
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Do you have access to the WIP and SubD tools? If so there is something like quad sphere. That could be then converted into a nurbs surface.—-Mark

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Yes, it seems very relevant. But, I need to understand one or two things first about Grasshopper to a bit modify and make use of this geometry.

Thanks a lot for your help.

11

Um, I don’t have access to the tools suggested by you.

However, based on your suggestion, I guess that the sphere geometry which looks simple is not that simple to construct. :neutral_face: :neutral_face:

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quad ball.3dm (342.9 KB) can this help ?

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Thank you @markintheozarks.

Not exactly. With this, I will end up similarly to the below setting (image attached) on increasing the mesh wire density, which is not desirable.

ErrorMsg-Rhino
ErrorMsg-Rhino1270×787 90.6 KB

It would be very good if I get something similar to the setup shown in the first image of this post.

14

half sphere.3dm (259.0 KB) is this closer?

1 Like
15

How’s this:

image
image1122×740 204 KB

In Rhino 6 use the test command TestQuadSphere, position and scale as desired (because the command doesn’t) and then trim off the upper half.

Regards
Jeremy

p.s.- test commands in Rhino don’t autocomplete so you will have to type it all in.

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Thank you @markintheozarks

Yes, now it looks very close to what I am looking for.

Although @jeremy5 has explained me the starting the point and other important things. But, your final geometry is looks more sophisticated. So could you please explain the construction procedure for the setup.

17

You could try testQuadSphere.

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Thank you @jeremy5.

This is very close to what I am looking for.

I was wondering if one can construct the whole hemisphere surface using a single patch rather than with the five patches…

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In the WIP , I made 2 quadspheres in SubD.scaled 1 smaller made an intersecting plane . Split both spheres by the plane. Split the plane joined up . Then converted to nurbs. Hope it helps. —-Mark

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I don’t believe that this could be done with a single patch (otherwise we’d have it in the toolbox!)

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