Hi gizmo,

> Can you only Boolean closed objects?

No, you can boolean open objects as well, however booleans are mostly oriented towards figuring out which pieces to keep and which to discard according to where they are located inside of a volume.

If the piece you want to cut is not a volume, it can be somewhat unpredictable which pieces will be kept and discarded.

In cases like that, switch to use the Edit/Trim command instead - it allows you to cut objects with one another similar to booleans, but you manually control which pieces you want to discard by clicking on them.

So in the case that you are describing use the Trim command instead.


> I've got the shell exactly how I want but how do I close it?

This would likely be easier with the method that I described earlier about building a larger surface first and them trimming it back.

When you build a surface like you have there with the corners of the 4-sided surface sheet totally smooth to one another, that will create a degenerate surface normal in that area and prevent some commands such as shelling or probably filleting from working in that spot.

That's another reason why it can be better to build a larger more simple structured surface first and then trim it, rather than trying to build a surface directly to your final outline which is more of what you would do if you were building with polygons - remember you are not building with polygons here, with NURBS it is generally better to use trimming and cutting type operations to make a final outline if that final outline is different than a 4-sided sheet.


> Here's an illustration of what I mean. How do I get these 2
> componant to be snapped together exactly.

The usual method is to find a key point like an endpoint and then grab the object close to that key point to snap on to it and drag it over to the matching point on the other object, Danny showed this above but also just to be clear here is a screencap:



- Michael