Hi Mike,
> Michael, these surfaces said they were joined, but upon closer examination, <...>
You can have surfaces that are joined together into a larger connected chunk of an object, while still having some various particular edges in there not joined to one another.
Here's an example to clarify:
That object is a "joined srf" because a "joined srf" just means that the object in question is made up of more than one surface joined together.
In this case the joined edges are these ones here:
This area here on the other hand did not get joined because there is too much of a space between the different surface edges there:
So that's the same kind of thing that you have there.
When the object type is "Joined srf" it doesn't mean that every edge is joined - in fact it actually means the opposite of that, that only some edges are joined and some are not, because if every single edge is joined to another one that will be labeled as a "solid" instead of "joined srf".
> when you separate the whole object set and try to join the surfaces
> in question separately, they refuse to.
This usually means that the particular edges have too large of a gap between them - the edges must have a maximum distance of only 0.005 units between them in order for them to get joined together.
> As I have discovered, Loft uses some type of interpolation, which means that the new
> Lofted surface intended to become the sides may have been an in-approximate
> representation of the large surfaces they were created to link.
By default Loft will do an automatic rebuild on each of the profile curves, that can generally help to even out the parameterization of the profiles before they become surface-ized and also to give all the profiles an inherently compatible parameterization which helps to make the final Loft result not be so dense with knots and control points. You can disable that by using the "Profiles" option in Loft - if you use Profiles: Exact then there won't be any interpolation/approximation step at all and the loft will go exactly through the profile without any rebuilding involved. But the Exact mode also means that the resulting surface's knot vector will contain the combination of the knot vector from every single profile curve together and also the surface will inherit any non-uniform parameterization so things like control point spacing can cause the loft surface to bunch or stretch.
But the rebuild step is supposed to rebuild to a tolerance of 0.001 units (unless you have set # of points mode of the profiles which does a much less accurate but also less dense resulting approximation), so it is supposed to be accurate enough to give a joinable result. If that's not happening then that may be a bug in the curve fitter - is it possible for you to boil it down to a simplified example of that problem, like just a file containing 3 curves in it and lofting between 2 of them at a time to generate a surface then does not join? If I had a reproducable example like that then I could probably verify if it is a bug or what.
> I was under impression that Join was good a working around these "near misses".
It is, up to a gap size of 0.005 - if your gap size is somethign like 0.006 units that's still pretty small visually and hard to see the gap without zooming in closely to the area where it is the largest.
> As you can see here, when exported, the polygons are now "matched" together and
> connected with no peering seam.
So that means that there is now a proper joined edge there now.
> Michael, I'd like to know a little about how Boolean Union lined these two edges
> up. Maybe they actually crossed?
> I invite you to also look at those surfaces in the provided model.
I'm not really following exactly what was booleaned. There does not seem to be any model attached to that particular message - in order for me to really follow along with what you are describing I'll need to have a more simplified result, like 2 objects set up to do a boolean union, then I can do the union and see the result rather than trying to reverse engineer some final result model for example.
Right now without simplified examples I just don't quite know the precise answers to your questions because it's hard for me to figure things out just looking at some big pile of surfaces - I don't know where to look or which particular spot the problem is in, etc.. etc...
So if you can simplify things, like "here are 3 curves, when lofted in pairs they don't join", or "here are 2 objects, when booleaned unioned can you give me some more information about the result in this spot here", etc.. would make it so I could better understand stuff and give more information back.
- Michael
