How to make a hot air balloon

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I’m planning to study the design of special shaped hot air balloons like this (image is an example), but I don’t know how the process should start, because what I’m wondering is The problem is how to balance it while hovering in the sky, and how to mesh it will be reasonable and optimal.
Hope someone has done it or has an answer for me, many thanks


Hi @dinhchien2103

It is a rather complex process to design and produce these type of balloons.

I think finding the volume centroid of the final shape will indicate the balancing, however what the final shape will be in real live as opposed to in 3D can be quite different.

In any case you will fist need to come up with a 3Ddesign that you than divide into 2D pattern layouts that can be stitched to create the 3D shape.

For flattening these pattern layouts in Rhino you can use Unroll as well as Squish.

Are you just studying the design process or planning on actually building these types of balloons?

Maybe @Steve_Howden can give some tips and tricks where to start.

Good Luck

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Thank you for sharing, I’m working on a real project

I don’t know how to properly divide each surface strip, can someone help me with this knowledge, or have any resources? I’ve been looking but can’t find it

Is there someone who has the same passion for hot air balloons as me, can exchange the method of implementation? or share with me if you are an expert, i’m very grateful

Have you tried the Ivy plug-in in the meantime?

Ivy plugin is here: Ivy | Food4Rhino

ExactFlat ($7000) is commercial flattening plugin. It is used to design complex balloons:
more info: Digital Patterning with ExactFlat and Rhino [McNeel Wiki]
and ExactFlat Software - YouTube

Non-Rhino comment: My guess is the balloon in the photo pressurized gas envelope surrounding the hot air envelope. Hot air will not inflate the leg below the hot air opening, The pressure differential between outside and inside is zero at the opening and increases with height above the opening. Also it would be difficult to keep air hot in the hands and nose.

FWIW, You don’t necessarily need very hot air in those. There are “valves” (simply pieces of fabric) between the main balloon and extremities that make that you’ll need quite a bit of external pressure to deflate those parts. Once airborne, the balloon will fly at the speed of the wind and there’s no real pressure that would greatly deflate those.
(I used to fly balloons 30 years ago and we also had a “special shape”, as they are called. At the time, my boss, Wim Verstraeten, set the world altitude record with that one…).