Boolean Union - Not sure why it's not doing it?

 From:  Michael Gibson
6739.4 In reply to 6739.1 
Hi ClosedCircuit,


> 1. Problem 1: I would like to join the 34 curves (a mixture of lines, arcs and circles) but
> MoI just laughs at my shortcomings and refuses to do so.

In MoI you can only join curves with just 2 segments that share a common endpoint, not ones that branching structures like you've got there.

A joined curve in MoI is basically for making longer and/or closed curves, a joined curve is made up of segments but the segments touch each other end-to-end forming just a single directional path with the end result.

That's basically because a lot of curve based construction mechanisms in MoI treat a curve as something that has a just one start and one end point and that follows just one path...

With something like you show there, if you want to process all those curves for something you can just select them all but you would not want to use Join on them because they are not set up with just 2 segments connecting at each juncture area....


> 2. Problem 2: Using these 34 curves, I've sweeped a profile and created 34 solids. I would like to
> Boolean->Union these solids, but MoI just laughs at my shortcomings, etc.

There are a variety of things contributing to that - one being that it's just more difficult in general for booleans to process things that have a whole lot of overlapping surface areas. But you've also got a lot of other things going on here that add further complexity - some of the pieces are not solids like with missing end caps which will make it difficult for the booleans to figure out which pieces are supposed to be kept and also some pieces are made up of joined parts but with self-intersecting pieces which really throw a monkey wrench into the boolean process as well.

Like for instance this piece here:



That's an open surface and not a closed solid because it's missing the front cap piece here:



With it not being a solid closed volume it will behave pretty differently than what you might expect when doing booleans with it, the booleans are more oriented around figuring out which pieces to keep or discard after slicing things with each other based on which solid volume they are contained inside of.

Then in addition to that the self-intersection is here - these 2 surfaces skim over some overlapping surface area:






That kind of self-overlapping surface skins will also mess up things that want to analyze solid volumes.


So there's still probably a fair amount of tune-ups needed on each piece before they'd be possible to boolean union, it may be better to just work using Trim instead which will let you work at a surface level instead of needing solids.

Hope this helps give you some idea of what's going on!

- Michael