Union problem

Hi all,

I have a problem with union. I tried some solutions I found on this forum, but nothing is working yet.

The thing I'm trying to do is to union two surfaces with a hole in it and I want to keep this hole. In the image below the two curves are separated and below that I tried to merge them.

For now I tried:
- solid union of the two boundary surfaces (gives error)
- solid union of the two breps (results in whole surface)
- region union of all curves (results in whole surface)
- intersection + difference of all curves (Empty Curve parameter at intersection)
- and many other solutions

The files are added to this post. I hope someone can help me, thanks.

Attachments:

union problem.gh, 15 KB
union problem.3dm, 698 KB

Replies to This Discussion

Permalink Reply by Arend on August 25, 2014 at 3:18am

If you use the clipper plugin it will work ok: only thing is they will be converted to polylines (seems to be not a big problem with this geometry.

http://www.food4rhino.com/project/clipper

Also, keep in mind that your geometry is very small, and has many variations that are within the tolerance of your document. It would we wise to change the units to mm, and even scale up a bit. (Or set your tolerance a bit higher, I need to use a tolerance of 0.00001 to get a good approximation of the geometry). The document tolerance is now 0.001.

Attachments:

unionproblem-clipper.gh, 5 KB

Permalink Reply by Bas van Wezel on August 26, 2014 at 1:10am

Thanks Arend, it's helping a lot! Everyone should use this component!

Permalink Reply by Thomas on August 25, 2014 at 3:44am

I see you have installed the Bowerbird plugin. Don't miss the last update (http://www.grasshopper3d.com/group/bowerbird). It also provides some boolean tools now.
Like Arend already mentioned you have to decrease the tolerance of your drawing or upscale your curves to get good results.

Permalink Reply by Bas van Wezel on August 26, 2014 at 1:13am

I tried bowerbird. It's working great for offset, but i had some union problems with it.

Permalink Reply by Thomas on August 27, 2014 at 11:19am

Oh yeah! I see the problem. I want that the boolean components work in the same way as the build-in components. But that makes it a bit difficult to define holes.

I released a new version of Bowerbird containing a new boolean component. It offers the possibility to set the fill type of the polygons (context menu).

It also calculates automatically the best possible value for the tolerance.

Attachments: