Untrimmed surfaces problem

Hi guys, i have a problem and maybe you can help me to solve it.

I have three coplanar trimmed surfaces that can rotate on 2 axys, but always stay coplanar. I need to make a boolean union to all the three of them, but sometimes, not every time, but only at certain random angles, the union is impossible and the warning message says boolean union is empty.

have you an idea of hou to solve it?

Thanks guys

Replies to This Discussion

Permalink Reply by Hannes Löschke on November 15, 2013 at 10:30am

Are your surfaces trimmed or untrimmed?

Anyways: Boolean Union is not meant to work with surfeaces. Boolean operations are defined for closed, solid Breps. I quess, you want to join all your three surfaces into one. There's a component called BRep Join for precisely that task.

Permalink Reply by Luigi Giovannini on November 19, 2013 at 3:05am

Well I tried also that, but the result of the union of three trimmed surfaces is sometimes an open BRep that merges all three components and sometimes an Open Brep that merges only two components and a trimmed surface.

Permalink Reply by David Stasiuk on November 19, 2013 at 3:32am

If they're coplanar surfaces, you should use the Region Union rather than the Solid Union...this will give you the boundary curves, which you can then pass into a boundary surfacse component.

Permalink Reply by Danny Boyes on November 19, 2013 at 3:52am

Might it have something to do with rounding issues. If you projected everything onto a Plane based on the first BRep would you get more consistent results?

Permalink Reply by Luigi Giovannini on November 19, 2013 at 4:03am

I tried That too, But it always has the same problem. I attached the file so that maybe it results all more easy to understand; you'll notice that if the two sliders named HR and VR are both zero, the final BRep join gives an Open Brep and a Trimmed surface, if you move them sometimes it gives back only an Open Brep and sometimes the error is repeated.

Attachments:

Grasshopper Surface Merge.gh, 14 KB

Permalink Reply by David Stasiuk on November 19, 2013 at 4:10am

can you internalize your surface data?

Permalink Reply by Luigi Giovannini on November 19, 2013 at 4:13am

No because this tool should be used to evaluate the area of the final BRep changing everytime the angles VR and HR

Permalink Reply by Danny Boyes on November 19, 2013 at 4:17am

Can you supply at least a picture as to what surfaces you have to start with and how many otherwise there is nothing anyone can do to help you

Permalink Reply by Luigi Giovannini on November 19, 2013 at 4:27am

Of course, I'm attaching the rhino starting file witrh which me tto I'm working: the larger trimmed surface is the one that has to be set on the first BRep in Gh, the smallest square one instead is the second Brep in Gh

Attachments:

Starting_Rhino.3dm, 642 KB
Starting_Rhino.3dm.rhl, 1 KB

Permalink Reply by David Stasiuk on November 19, 2013 at 8:53am

This one is tricky. I've inverted your logic a little here...basically, I'm using your projected surface boundary curves to split the tile surface. Then I'm testing the midpoints of all the naked edge curves from the split pieces to determine if they are bounded on both edges by your base projected surfaces. If a surface has at least one edge that is bounded on both sides, then it falls "inside" of your desired boundary. These are kept, brep joined, and then face-merged to give simple planar boundary surfaces.

Attachments: