[OpenSCAD] F5 works, but F6 gives: ERROR: CGAL error in CGAL_Nef_polyhedron3():

Ronaldo Persiano rcmpersiano at gmail.com
Wed Jan 17 17:34:03 EST 2018


Here is another interesting case. The hull is a tetrahedron but the inside
polyhedron was defined with just one face ( a simple list of all vertices).
It is surprising that the preview of the polyhedron alone is correct but
the preview of the intersection with the sphere is void.

intersection(){
  hull(){
    polyhedron( points=[[0,0,0],[0,10,0],[10,10,0],[0,0,10]],
                faces =[[0,1,3,2]]);
  }
  sphere(8); // the preview is correct when this line is commented
}


 The same render comes to light for any order of vertices in the list faces.

2018-01-17 16:06 GMT-02:00 Ronaldo Persiano <rcmpersiano at gmail.com>:

>
> ​Interesting workaround! It is "reasonable" since the hull operation
> depends only on the vertex positions. So, missing facets in a polyhedron
> are irrelevant.
> For instance, this code renders fine:
>
> intersection(){
>   hull(){
>     polyhedron( points=[[0,0,0],[0,10,0],[10,10,0],
>                         [0,0,10],[0,10,10],[10,10,10]],
>                 faces =[[0,1,2],[3,4,5]]);
>   }
>   sphere(8);
> }
>
>
> ​If you drop the hull, CGAL complaints.
>
> 2018-01-17 14:10 GMT-02:00 Uwe Schächterle <corpsman at corpsman.de>:
>
>> To inform the ones that are interested in.
>>
>> The Problem under Linux still exists, but i found a workaround.
>>
>> if you write
>>
>> hull()
>> {
>> }
>>
>> around the polyhedron then F6 is possible under Linux too.
>>
>
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