# What command to fit a surface encompassing selected objects?

Steve, couldn’t you make a curve around the objects and extrude it?—-Mark

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are u referring to “Drape” command?

Kudos for the fish!

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Hi, thanks for trying , but it must hug the items, it is to represent a gift paper wrapping for example, so needs to touch, be taught and take shortest route between edges of objects, so imagine a desktop fan, various objects such as base and plinth and fan chamber, and a surface over these just as if it was gift paper wrapped, fan being boxless ! as one places paper over and pulls on it, it takes up least distance between the bits that stick out !

Steve

You’re looking for a “shrink-wrap” function in Rhino, that does not exist natively - although some inroads are being made, but I’m pretty sure it will not happen very soon.

the closest tools probably using kangaroo. here is the link for it:

Here’s another version of shrink wrapping with kangaroo

Though if you’re after something faceted that encloses the objects without curving into the gaps, you might also want to look at the convex hull component in RhinoPolyhedra. (You’ll need to convert your input geometry to points)

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why dont you just use patch, mesh the objects to extract a few relevant vertices, if needed make a quick loft around the perimeter for tangency.

Consider Steve’s version? V5.14

Have you tried the “! _Drape” command?

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Hi.
Has no one gift wrapped an odd shaped item before ?

B Design Bg2.
I tried drape and its no good at all, it is more like vacuum forming a sheet of plastic down over objects.
Imagine you have a sheet of gift wrap paper and you wrap up an object, the sphere and the block need to be joined as an object is one item not three.

so lets fuse them together as some kind of strange sculpture. there must be no droops between the items making up our object. When I place gift wrap paper around an odd shaped object it takes up a straight line between the bits that stick out, it doesnt drape outwards to a floor area. As fot having to try and draw the lines that form the limits of the surface, no.
I have just triesd to draw lines from the oustide surface of those two spheres to edges og the cube, and when you rotate the object the lines have gone elsewhere,. This needs thino itself to identify the objects and place a wrap hugging all surfaces and following shortest distance between objects.

Steve

That does sound like the convex hull is what you are after.

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Daniel, how did you do that ?
Steve

It should be something like this, but in my example it does not include the sphere, it only works with flat faces

with mesh works better

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Yes, I think converting to mesh will be necessary.
For flat surfaces, as long as there are vertices at the boundaries/corners they will included exactly in the hull. For curved surfaces you’ll get an approximation, its accuracy depending on how dense the mesh is.

While I suppose it is theoretically possible, I don’t think I’ve ever seen a convex hull algorithm that works with NURBS directly.
For certain simple cases it would be possible to generate it manually, but making something that would work automatically for all cases would be tricky.

For points though, it is a well studied problem, with good methods available. There’s a component for it in:

and also in:
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I tried the RhinoPolyhedra Convex Hull and got curves rather than surfaces. Is that expected?

Yes, it outputs polylines for the triangles. These can be easily converted to a mesh though:
convexhullmesh.gh (136.2 KB)

Thanks Daniel,
Good to see we can use Rhino for chocolate bunny packaging design!

Jeremy

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i would rather wrap flowers with that method, bunnies like it tight to feel sexy

Hi,
v5
wow that will be perfect for what I need, thanks.
Now to get started and learn Grasshopper to find out how to use it.

I presume it will work in V5.

Cheers

Steve