Which “Cross-section curve options” are you using? Make sure you select “Do not simplify” or “Refit within” if you want a tighter tolerance between the curve and the surface than the one set in the file.
Your number one problem is your reliance on Booleans
If you would learn to use Rhinos surface modeling tools you would get the job done 10 times faster and end up with a lot better quality model.
In the enclosed file the blue and green surfaces are the only
part of your model that is relevant to what you are trying to accomplish. After reducing the problem to just what is relevant, it becomes simple to complete the model. Just use trim command to trim away the parts of the blue and green that you don’t need and then join everything. After that you can fill the one hole with a simple sweep2 surface.
I was not relying on booleans here. I pointed out that neither boolean nor surface operations work works. I have presented a simplified version of the larger problem here. What I have in this particular case is that I can split A with B and B with A but I cannot do the two operations in sequence. After I split A with B, I cannot split B with A.
You summed up the cause of your problem with this statement in your first post:[quote=“bigjimslade, post:4, topic:41388”]
I am trying to add the three closed solids.
Why waste time creating all the extra surfaces to make 3 closed solids?
The probability of success will increase if you reduce the problem to just the surfaces that intersect. Adding more surfaces that aren’t needed will only increase the chance of failure.
I created it using Trim to eliminate the internal surfaces. To trim several surfaces I needed to use Intersect to create a curve to trim with. I also needed to explode one of the polysurfaces and trim the individual surfaces.
That’s is it. The reason for asking why is that area is actually more complicated.
This is a a work in progress so it will be more complicated than this. I was just testing with a simple block first and finding that did not work. This does not work either—obvious if the simple does not work, the complicated will not either.
The reason is Split is the wrong command, Trim is the correct command to use.
If you think about it the answer to your question is sort of obvious, After you split one of the objects its no longer the same object. If you want to do what you suggest then make a copy of the first object you split to use to split the second.
But using Split command here is bad technique. Your model is an example of why its bad to use Split and good to use Trim command. Either one might succeed for doing the cutting, but if you want the objects to join after the cutting the Trim command is more reliable to make sure that happens correctly. The short explanation of why, is the Trim command calculates both the new boundaries at the same time and that pretty much guarantees the 2 polysurfaces will have matching boundaries that join up. If you do 2 separate split commands there is no guarantee that the edges will match up and join, particularly at the end points of the edges (vertices).
Doing 2 split operations on intersecting polysurfaces is a good way to end up with failed joins or the tiny orphaned edge loops at the end of edges that are supposed to match.