recursive union in C#

Hi Guys,

I am writing a script to create a recursive boolean function in c# and I reached a good level where all the intersected geometries get unioned. Some times there is a brep that doesn't intersect and that breaks the loop before it starts. Now I am looking for a method does something similar to this :

List<Brep> unionedParts = ...;

List<Brep> Leftovers = ...;

double Tolerance = 0.1;

if (Brep[] Brep.CreateBooleanUnion(unionedParts, Tolerance))

{

___Continue the operation___

}

else

{

Leftovers.AddRange(unionedParts);

};

Can anyone tell me how to do it pleas?

I am in a rush .....

Replies to This Discussion

Permalink Reply by peter fotiadis on June 14, 2016 at 5:07am

That's very easy. Just post a test case with these Breps of yours

Permalink Reply by ghaith Tish on June 14, 2016 at 6:22am

Curve[] lstCrvs ;
    Point3d[] lstPts ;

    bool N = Rhino.Geometry.Intersect.Intersection.BrepBrep(x, y, 0.01, out lstCrvs, out lstPts);
    A = N;
    B = lstCrvs;

This only outputs aTrue value. What does this True refers to ?

Permalink Reply by peter fotiadis on June 14, 2016 at 6:40am

Still no test "items" provided. That said ALWAYS do that regardless if you think that's irrelevant/not required.

After that all the answers could be on hand.

Permalink Reply by ghaith Tish on June 14, 2016 at 11:20am

Hi,

Just Uploaded the files so you have a look.

I just want to know how to store the unioned geometry before the loop crashes. I have made a condition for an intersection event but it didn't succeed because sometimes there is an intersection but no union and the loop crashes.

Attachments:

UnionQuestion.3dm, 3 MB
UnionScript.gh, 9 KB

Permalink Reply by ghaith Tish on June 14, 2016 at 11:32am

The only alternative is that I will go for a trim instead because if there is an intersection there will be a trim.

Permalink Reply by peter fotiadis on June 14, 2016 at 1:37pm

Well ...

1. For a vast variety of reasons I would strongly suggest to adopt some sort of "sequential" item access policy (like the one used here by sorting the box centers "along" X). Of course NOT all the cases allow that ... but anyway. Additionally always take some provision with regard how many "items" to process.

2. For some reason your Breps slow down an already struggling Rhino (Rhino is pathetic in anything related with "solid" ops: expected since is a surface modeller).

See yours:

VS mine:

3. Exploit the C# in order to get the gist of the whole policy used: what is the "failures" DataTree, what is the current union result etc etc.

Attachments:

Union_breps_V1.gh, 126 KB

Permalink Reply by peter fotiadis on June 14, 2016 at 2:09pm

BTW: Of course this:

Brep[] uni = Brep.CreateBooleanUnion(bList, tol); [where bList is the demo Breps used]

makes an Array of Breps - at once (with a little dose of Karma)

BUT ... if you do that in your Brep List you get null (explanations later).

Permalink Reply by ghaith Tish on June 14, 2016 at 7:20pm

Fair enough ! Many thanks. Awaiting the response of why the pipes give null value during a boolean. These pipes has been created out of lofted circular crosssections !.

Permalink Reply by ghaith Tish on June 14, 2016 at 7:34pm

Is there a way to break the loop before the null value occurs ? because boolean union method never outputs an Event boolean so it will always run and crash. for me it is enough just to get the pipes unioned till one of them breaks the loop. if not what the plan B could be like ?

Permalink Reply by peter fotiadis on June 14, 2016 at 11:45pm

Appears that's time for the trad update: the V2, that is (more checks [VS tolerance], far more elaborated loop control, explanations [inside the def], more complexity, slower, 2 divisions by zero [for the brave] == progress).

BTW: sorted pipe N1 ("along" X) doesn't intersect with the rest

BTW: planar union BrepFaces are a clear mess (it should be one BrepFace).

BTW: Instead of Lofting (case: pipes like yours) use the approach as found in the "small" C# that prepares the demo Breps ("extrude" at once a BrepFace [both sides or not], that is).

Permalink Reply by peter fotiadis on June 15, 2016 at 2:00am

Here's the V2.

More freaky options than Sahara has grains of sand: this is what we call progress these days => making a "simple" task utterly chaotic for no reason (kinda like Windows), he he.

Use rather the demo in order to get the gist of the whole thingy. Notice that the AtOnce option occasionally fails (but s#%@t happens all the times in this business).