Boolean Union (surfaces) error. Makes object disapear

[Anonymous]

Hello Autodesk community,

I have a problem with the booleans commands, if I apply it to very simple shapes such as a cylinder and a sphere or two cylinders it works perfect. But if my surfaces are a bit more complex (for example a lofted surface) they produce a number of different errors:

-many times one of the objects dissapear

-it shows an error: "operation has history, inputs are not detected" (I attach screenshot)

-it only trims a part of the object

it also makes the program crash.

Any advise?

Is there any other way to merge surfaces that is not using the boolean operations?

Thanks!

[mspeer]

Hi!

Please upload a scene-file with the 2 objects.

[Anonymous]

Hello,

Thanks for replying. I have attached my scene file as a zip file. There are various objects there. One is a dolphin in which I would like to attach flippers and fins. The booleans don't work there. Then next to it there are two simple cylinders in which booleans work fine and the third combination of objects is another cylinder with the dorsal fin, in which booleans make the fin disappear (sometimes the program crashes).

The fin and flippers are lofted surfaces and the dolphin body is a revolved object, but non of them are very complex, I thought I could use booleans to merge them together.

I hope you can give me some advice. Thank you!

[mspeer]

Hi!

Thanks for uploading the whole scene, so i could see that your fin is created from several Bezier Curves. These Curves are not "really" closed, if you use Curves -> Open/Close an additional curve point is created and moved to the same position as the first one. You could move one of them see it's not a "really" closed curve.

Use CV Curve Tool and one of the available settings (not Bezier) to create a Curve that "really" can be closed by Curves -> Open/Close. A lofted surface of closed curves will result in a closed surface and this will work with Booleans.

[Anonymous]

Hello!

Thank you very much for replying and very much appreciated your comments. Does that mean that bezier curves cannot be really closed?

What you say about the CV curve is correct, if I create a CV curve, close it (with the curve open/close command) and then use to make a lofted surface I can do the booleans with a cylinder.

However, I really need to use bezier to model the fin, as it is the only way to create a curve with a nice corner. Is there not a way to "really close" a bezier? I tried using the CTRL + SHIFT + LMB from the bezier curves menu but it has the same result. It looks closed but then when I try to use to do a booleans operation it gets erased.

The other problem I still have is that even if I used a lofted surface created with CV when I try to do a booleans union with the body of the dolphin (which is a revolved surface) it produces the same error and also makes the object disappear.... And this one I don't quite understand, because the cylinder (nurbs primitive) is also a revolved surface and it works with it!

I attached a jpeg (and also my scene again). There are various combinations of objects:

Left: Body of dolphin + lofted surface made of CV curves = Doesn't work (the lofted surface dissapears)

Right: Cylinder + lofted surface made of CV curves (same as before, I copied it) = it works fine

I also tried with just the body of the dolphin and a standard cylinder and still Doesn't work....

Any other advice? Thanks!!

[mspeer · Accepted solution]

Hi!

1. You can't make a "really" closed curve with Bezier Curves.

2. You can make a nice shape with CV Curve. Tip: Curves -> Open/Close in options set Shape to "Ignore".

Example with closed CV Curve (3 Cubic) and only 6 points (you can use any other Curve degree and as many points as you want):

3. In your last provided scene "...boolean tests.ma" turn off in Viewport: Lighting -> Two Sided Lighting, then you see that your normals on your dolphins are reversed or better said, that you have a different surface direction with your dolphins than with your fin.

4. Select your second Dolphin (the one in the middle prepared for Booleans) and in Main Menu: Surfaces -> Reverse Direction.

5. Do Booleans -> Union Tool with Dolphin and fin and it works now.

[Anonymous]

Hello again!

Cool!! That totally worked 🙂 (when I turned off the Two Sided Lighting I saw the reality (I attached screenshot). After struggling a few days with this I'm really grateful for the good advice and the detailed instructions. Thank you!!

And also thanks a lot for the tips in making CV curves, I'll definitely try them.

All the best!