Hi Petr, thanks for reporting it, it looks like it has to do with the order the objects are being processed in.

It looks like when trying to union together the 2 "outside" circles that do not intersect first, it is getting confused at that point and not making the proper result, but only when the 2 non-intersecting objects have reversed directions from one another like you will get with a mirror.

When you do 2 intersecting ones manually, or edit the objects in such a way that their internal ordering in the geometry database has changed, then that can make it work since it will process 2 intersecting ones at first instead of 2 non-intersecting ones.

I'll dig into it a bit to see what is involved in fixing it up.

- Michael

this bug arrives when you have a lot of "circles"
but works when you select a few circle make the boolean etc...
so can be named that a real bug?

Hi Pilou,

Yes it is definitely a real bug - it is not just with "a lot" of circles though, it has to do with having circles that are going in opposite directions from one another, like one going in a clockwise direction, and the other in a counter-clockwise direction, combined with a certain ordering of them.

It won't happen if you have a bunch of circles created by array for example, because those have all the same clockwise or counter-clockwise orientation. But when using mirror the second curve created will have an opposite clockwise orientation.

It does not look like it should be very difficult to fix.

- Michael

Hi Petr, I have now fixed this bug for the first v2 beta.

Thanks for reporting it with such clear steps to reproduce it!

- Michael

How about a way to change the direction of things? "shift click" or something reverses direction of object.

Thanks.

Hi Burr, stuff in MoI is set up to automatically adapt to different directions on curves and such, so it shouldn't normally be necessary to do any kind of manual flipping. This happened to be a case that was not doing it properly but it is fixed up now for v2.

I would still like to add in a function to reverse things at some point because it can be useful to know and flip which direction will be the "outside normal" direction for surfaces that are exported to a polygon mesh file. If you have a closed solid then normals will automatically be oriented outwards, but that won't happen for just surfaces instead of solids.

But that really needs a bit more UI for the "flip" command, because you need to not just be able to flip but also to see what the normal direction is currently.

- Michael

Hi Michael,
I've noticed it's not only with circles, does the fix cover all closed curves ?


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Hi Danny, yup the fix is a general one that covers all closed curves that have a different winding direction (clockwise/counter-clockwise) from one another.

- Michael

So a good hunting trip :)

Great catch guys - can't wait for the beta!

-Will