Unroll a oblique cylinder shaped vault

[rai_gar]

Hi! I can't get a decent result using the unroll command on the vault of the image. This is a portion of an oblique cylinder. I've made several attempts, but I think the problem is the non-straight axis of the cylinder. I also tried to rotate the surface so that it was a portion of a straight cylinder sectioned above and below, but I didn't get a good result.
Could you help me, please?
Thanks

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Plan view

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[daniel]

Indeed, I guess you need the cylinder to be straight (axis along X, Y or Z).

How is the cylinder before the unroll step? (there are some missing images sadly)

[rai_gar]

Hi Daniel, thank you for your very quick response. Here are some clarifying images.

vault.jpg (1011.7 KiB) Viewed 5359 times

[daniel]

Hum, have you tried to fit a cylinder on this cloud? (with the RANSAC shape detection plugin)

And then use this cylinder to deduce all the parameters? (and also to make the cloud "straight")?

Otherwise, don't hesitate to send me the cloud file so that I can try it on my side (admin [at] cloudcompare.org)

[rai_gar]

Hi Daniel. I tried with the cylinder because I read this suggestion in another post, but I didn't get a good result.
Thank you very much for your availability.