Problems with Trim Solid

Replies to This Discussion

Permalink Reply by Joseph Oster on December 28, 2015 at 2:40pm

No code, no answer.  It doesn't have to be the entire file.  It often doesn't matter how you got a curve or surface or solid, only what you want to do with it where it fails.  You can use "Internalize data" to save the geometry for the very last step or two that is giving you trouble.  In other words, create a SIMPLE Grasshopper file that isolates the problem and post that.

Permalink Reply by Elisabeth on December 28, 2015 at 3:27pm

here is the box, in Rhino and GH

Attachments:

• box.3dm, 148 KB
• box.gh, 11 KB

Permalink Reply by Joseph Oster on December 28, 2015 at 3:51pm

Hmm...  Well, I don't have LunchBox installed (is that necessary here?) and am not quite sure what 'Isotrim' does(?) but think I see the problem.  The Brep faces are trimmed surfaces and 'Isotrim' works on the untrimmed surface.  This looks very manageable, someone else might be able to help.

Perhaps something like 'Untrim', 'Copy Trim', 'Retrim'...?  What is the objective?

P.S.  If you right-click on the 'Brep' param and click "Internalize data", you won't need the Rhino file.  Great job in breaking the problem down to manageable size!

P.P.S.

http://www.grasshopper3d.com/forum/topics/when-subdividing-a-trimme...

http://www.grasshopper3d.com/forum/topics/how-do-you-divide-a-surface

Permalink Reply by Elisabeth on December 28, 2015 at 3:09pm

Thank you, the Rhino file is about 500 MB, with many layers, i try tommorow. make a small file with my problem, It is getting late evening.

Permalink Reply by Joseph Oster on December 28, 2015 at 4:51pm

Is this cheating?  Reconstruct the faces using 'EdgeSrf'...

Brep is internalized, no need for Rhino file.

Attachments:

• isotrim_2015Dec28a.gh, 58 KB

Permalink Reply by Fred Becquelin on December 28, 2015 at 5:13pm

Hi!

In Rhino a "Surface" has no trims. If a surface has been cut, then it's a "Brep" now.

As a result, any GH component that accepts a "Surface" type looses the trim info.

(this should really be in the faq... because it is one!)

The simple way is to explode the box in Rhino, select all the faces, run "_ShrinkTrimmedSrfToEdge" (and rejoin).

However there are ways to run a rhino command from gh, look for that in the searchbox.

Fred.

Permalink Reply by Elisabeth on December 29, 2015 at 9:14am

Hi Fred,

Your explanation makes me understand the problem, I used the shriktrimmedsrfedge command and , it worked, now i have another problem

At the now skrinktrimmedsrf box, i have a top surface and 4 sides, if i use isotrim at the sides, the subdivede start from the top of the side going down, because the extrusion orginal was in minus z direction, so the divide srf follow the roofedge of the box, instead following the groundedge at the box.

Maybe i need flip matrix,or reverse list, but my head is not that expirienced. Have you an idea?

Thanks a lot,

ELisabeth

Permalink Reply by Joseph Oster on December 29, 2015 at 11:24am

This new problem could well be a result of my code, if you used it, instead of "because the extrusion original was in minus z direction".  You can tinker with the sequence of edges connected to 'EdgeSurf', for example.

Permalink Reply by Elisabeth on December 30, 2015 at 5:04am

So far exploding the Brep in edges and making new surfaces, looks a good solution.

With the new surfaces all old data is deleted.

It is a  problem with the orginal trim,

Thank a lot.

Permalink Reply by Joseph Oster on December 28, 2015 at 7:07pm

This one splits the faces of the Brep without reconstructing them BUT...

1. it works with only one surface at a time (unlike the 'EdgeSrf' solution)
2. it expects four edges on each face
3. the results of 'SrfSplit' are in a somewhat chaotic order
4. it sorts the edges by the Z value of their midpoints, which might not always work?

Attachments:

• isotrim_2015Dec28c.gh, 66 KB

Permalink Reply by Joseph Oster on December 29, 2015 at 7:53am

Instead of using the results of 'Curve On Surface (CrvSrf)' with 'SrfSplit', this one uses them to re-create the surface using 'NetSurf', then uses 'Isotrim (SubSrf)', which produces a well ordered list of sub-surfaces - very similar to the 'EdgeSrf' solution, perhaps even identical, but potentially more accurate because it uses more UV lines instead of just the edges.

'Sort Edges by Midpoints' is also improved(?) here, but this code still suffers from two of the limitations noted with isotrim_2015Dec28c.gh:

1. it expects four edges on each face (same as the 'EdgeSrf' solution)
2. it works with only one surface at a time (unlike the 'EdgeSrf' solution)

Attachments:

• isotrim_2015Dec29a.gh, 73 KB

Permalink Reply by Elisabeth on December 29, 2015 at 9:04am

Hi Joseph,

Thank a lot for your several codes to answer my problem, i think all your solutions is great, you did realy great, i dont  know what i prefer, i need work......and check the most suitable...

Elisabeth