Hi Anadin, there isn't any way to automatically get simple clean geometry if your starting point is messy and complex geometry...
If the base geometry contains lots of overlaps and gaps between different pieces then that's going to cause overlaps and gaps in the meshes that are generated from them.
You're probably looking at a lot of reconstruction and remodeling work in order to fix things up.
> The problem I have is that they end up with a lot of overlaping and internal geometry not to
> mention the fact that the curved sections verts almost never line up.
Certainly if you've got 2 pieces that are just completely pushing through each other there won't be any specific vertex alignment between those pieces, separate objects will get meshed separately without knowledge of each other and they each will have their own vertex structure.
In order to have vertices aligned you need to intersect parts like the selected object you show in your screenshot above with the surrounding areas to combine them together. When pieces are combined and share a joined edge between 2 surfaces, that's when the mesher will do some extra work to ensure that there is a unified vertex structure along that common edge.
If you've got surfaces that look like they are meeting up but still do not generate unified vertices it probably means they are not actually joined there - it is possible for some edges to get joined but not others if some of the edges have too large of a space between them. Unjoined edges are also called "naked edges", and it can be useful to set up a shortcut key to identify naked edges as described here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4869.5
But it will probably take quite a bit of work to fix up things that are messy, you seem to be asking if there is any magic button to push that will automatically solve all problems, and I'm sorry to have to tell you that there is not any thing like that...
Sometimes if you have an object that has just a little bit too large of gaps between edges to get things joined well you can try to use Edit > Separate on it to break it back down into individual surfaces, then scale it down by 1/10 in size (select it, run Transform > Scale, type 0 and push Enter to specify 0,0,0 as the scale origin and then type 0.1 Enter), then do the join and then scale back up. Scaling down will also scale down the gaps between edges and sometimes that can bring them into the join tolerance.
Also another tip - ask the people generating the files if they can give you more than just IGS format, try asking for STP/STEP format in addition to IGS and try using that to see if it comes over better. IGES format usually transfers data as a big pile of individual surfaces, which then leaves the receiving application to do a lot of work to figure out how to rejoin things. STEP format can transfer solids which maintains the joining information inside the file so it can avoid some kinds of joining issues. Sometimes there are other different problems with STEP as well though, so it's not a bad idea to ask for more than one format if possible. If they can generate 3DM or SAT formats, ask for them and try them as well.
- Michael
