Getting a closed envelope (mesh?) around surfaces


I need a nudge in the right direction. In the example file is a parent object and some child objects.

What I need is to compare the volume and surface area of the parent to the volume and surface area of the children (excluding the parent intersections).

I have tried this approach, but it seems to be so heavy that I can´t even compute the example file geonetry (turned into mesh). Besides – the “wrapping” isn´t all that precise for concave shapes. By the way the precision ought to be around 5% both ways.

My guess is that meshes are the way to go because attenpting to join and split complex and sometimes slightly misaligned nurbs surfaces is quite an undertaking manually (being the reaspon for this script). Instead a mesh envelope that follows various unjoined (almost random) surfaces seems like a good idea.

Which way should I look? Does this need to be scripted from scratch?

Example.3dm (106.0 KB)

In your example it works to use Solid Union.

What kind of geometry do you have that this doesn’t work on?
That shrink wrap example you link isn’t really for this sort of thing - that’s more about shrink wrap in the literal physical sense of wrapping a stretchy material onto the shapes.
If it’s just about taking a bunch of shapes and making them into a closed solid there are several better ways.

Example.3dm (525.0 KB)

You are very right sir – I wasn´t thorough enough with my example.

This new example is closer to the calculated objects. I solved the underside hole by meshing the objects and using pufferfish “close mesh” but I don´t know how to properly join the meshes to create single surface and I don´t know how the split surfaces will work (although using solid union beforehand could pretty much solve those).

You can fill the mesh holes before the union step: (228.7 KB)