Why Split fail here?


V5 not sure split is failing here. Why split fail?

red object is the cutter.

split erorr.3dm (181.7 KB)

From your picture it looks like the splitting object does not go completely through the object to be split. Split won’t work unless it does.

The intersection of the object to be split and the splitting object cannot end in the interior of the object to be split. The intersection has to be either a closed curve or a curve which starts and stops at the edges of the object to be split. Intersect the two objects and examine the result.

What are your trying to accomplish with the split?

I have selected object want to split by red object.

I have checked intersect the two objects, but only two intersect curves. that show three intersect curvs was right.

Intersect appears to be not working properly. There should be three curves.

However, if Intersect worked properly Split would not work because the intersections would end in the interior of the surfaces.

How to do with this?

The red surface needs to be bigger than the object to split

Hi Alen – this is a bug in the intersector - to work around it, use InsertKnot on the curved surface with Direction=Both and Automatic. The resulting denser surface intersects correctly.


Hi pascal,

Thank you!
Does this bug can be fixed in v6? Some times found this bug in the project to make work fail.

Hi Alen - this case does not work in V6 either, actually - I am putting it on the bug list for the developer to check - thanks for sending it in.

@pascal OK,thank you

you can also change your absolute tolerance to 0.4 - 0.5 units it intersects and splits then


Can, maybe, but don’t… the trims will be imprecise and likely to cause all kinds of problems later. Edge tolerances on the resulting object are miles off.


where for example would that cause problems? when i split and reset the tolerance it still joins back together without problems. do joining and splitting/intersecting deal with different tolerances?