I unioned the 'cupola' which was built by a revolve, and then squished with a scale, to the body, and besides the trim line where the 2 join, there is a loop that goes down into the body...



also, when I click on the cupola, it appears there are two surfaces. But I can't drag or get rid of one of them. If I select it, and hit delete, the surface totally disappears...



Okay, wait, I just got it to work. I deleted one of the surfaces, and it looks like we got funky geometry on the inside....



I also attached the 3dm file, where the two pieces haven't been unioned yet, so you can try it yourself...


Hmm, I saved the file with the non-unioned pieces, and when I tried to reload it and do the union, MOI crashed. I did this because it seems that revolve sometimes doesn't generate a closed surface, until the file is saved and reloaded...

Okay, tried it again, and it crashed again.

You have posted an explosive starship :)
As soon as we approach it, Braooooum !)
Maybe the cupolla was made with TnT?
Seems the best is kill this Cupolla, and remake another one with another method :)

No it's not the cuppola, if you Copy / drag out and make an boolean operation with another new volume that works!
It's the Starship the problem :)
Seems boolean operation Union of it composant are not clean!

There is some weirdness i their somewhere. I'll admit. But when surfaces don't align properly, MOI generally doesn't let you join them. The starship behaves like it is a closed solid. I'll poke it further.

I tried to seperate all the surfaces that make up the ship body, and poke at them, and Moi crashed when i did that.

Something definitely wrong.

Wait the next version with the "Red Square Alert" when points are overlaping :)

Yeah, the problem is with the main starship body, it has gotten messed up.

After deleting the generator curves, I can tell by looking at it that there are some duplicated surfaces in it, you can kind of see some edges look heavier than normal if you look closely, this is an indication that two edges are being drawn on top of each other which means multiple surfaces.

This is again another one of those things that will kind of semi-heal itself if you save it and reload it.

After doing that here, it is fixed up to a certain extent, and there are some duplicate surfaces that have been automatically separated out, dragging them around I can see this:



See that highlighted piece? That's a vertical plane that is embedded inside of the starship - it is what is causing problems and also responsible for the downward intersection edge that you saw.

This is what's called a "non-manifold" edge - one where more than two surfaces have become glued together along a common edge. Do you remember how that front piece got put together with the main body piece, was it through join? I think there may be a problem right now if you try to use Edit/Join on things that share a common surface (instead of just common open edges) - I think it may cause some problems along these lines.

If you can remember how that front piece was welded to the main body it could help track this down a bit more.

- Michael

Does exist like "red square" for points, the same alert for surfaces?

> Does exist like "red square" for points, the same alert for surfaces?

Nope, not yet.

Some surface problems aside from stacked-up points are hard to detect without a difficult calculation...

Some things like this are not so much something that you should avoid doing (like the stacked-up points), but instead they're more bugs in specific commands where the command itself needs to be fixed up.

- Michael

Well, I can't delete it, because that causes a crash, and I can't seperate because that crashses as well.

I don't know quite how it got there, but it apparently makes a lot of commands unhappy.

Well, the front part was created via a revolution. But it's weird that is the area shoudl exhibit other curves.

The body was rail revolved.

The spurious capping plane, I don't remember from where it came from.

Okay, the lil half-saucer shape under the cupula, I can't get it to weld with the other parts. So it seems MOI is not satisfied that the edges line up enough to join it with anything else.

There is a half-circle shape on the underside as well, and it refuses to join with pieces as well.

Deleting them, and performing a blend, the resulting shape works fine, and I can join the starship back up again.

> Well, I can't delete it, because that causes a crash, and I can't
> seperate because that crashses as well.

After you open it, immediately save it out again as a new file, like starship2.3dm. Now open starship2.3dm and you should be in better shape at that point. But there will be some duplicated surfaces that you will want to remove.

I think that trying to join 2 pieces that have coplanar faces may be the cause of this.

- Michael

Another weird thing. I have a curve, it's complete and joined. Yet when I extrude a circle over it, it looks like one solid piece, but 3 of the pieces aren't joined. I try joining and union, and it doesn't work. I can drag the seperate pieces around.

I'm attaching this version as well. file as well. There is a small circle floating near the curve I am using.

Here is a image.

The yellow bits are 2 seperate piece, even though the curve that created them is continuous. I looked for overlapping points, or other probs, and couldn't find any.

It doesn't pierce the command bridge, it just looks that way. I moved it out to make it easier to see. I'm using these sweeps to cut paneling into the spaceship

Hi Crusoe, I'm not following this last bit - I see the circle and I extruded it, but I'm not seeing what is messed up.

- Michael

Ok, I see - this is with a sweep, right?

Found the problem. Where the loopy bit breaks into a seperate segment, there was a 'corner' point from when the segments were welded together. Deleting that corner point allowed the extrusion to succede over the whole curve


Are there any plans to allow users to change "corner points" into regular points and vice-versa?

Yeah, it's a sweep.

Yeah, that spot had a tangent difference of 0.68 degrees between the different pieces.

Not much, but enough so that the edges had enough of a gap to not join.

> Are there any plans to allow users to change "corner points" into regular points and vice-versa?

Yes, I think eventually I'll try to package this up, probably when there are object properties for the selected object, possibly this will be a changable property on selected points in the same properties UI. It will be a while for that though.

In the meantime you can do the equivalent of a change by inserting a new point and deleting the old one.

- Michael

What is weird, is corner #1 causes the sweep to break into a seperate point at that place.

But corner point #2 doesn't.

I moved the points to show them better. if I delete #1, the sweep forms one continuous piece.

> But corner point #2 doesn't.

That's because the 2 segments that are touching at that point have matching tangents. So even though it's a "corner" point which will make a kink if you move it around, it is completely smooth at that spot in its current point arrangement.

Since each segment has the same tangent direction at that spot, the edges of the resulting surface match up there as well.

The other one that was a problem seemed to look smooth to the eye, but it was off by just enough (0.68 degrees) to make a non-tangent area in the curve right there.

- Michael