Precision on Mesh

Hello everyone, I want to know more about the details of certain elements such as grids.

When I draw by hand edge of a mesh, or I run the command "dupborder" I get two different results.
With grasshopper I get exactly the same as the order ereur dupborder, trying several techinque.

I am forced to work in networking for the creation of land, how can I get the real border, or even the true vertices?

It is there any problem with the mesh?

Mesh vertices and ligne drawing

Distances on grasshopper

Replies to This Discussion

Permalink Reply by Rémy Maurcot on January 11, 2012 at 7:39am

I found this on the net, but the link leads nowhere.

http://wiki.mcneel.com/developer/rhino/5/sdkfeatures#double_precisi...

http://wiki.mcneel.com/developer/rhino/5/sdkfeatures/doubleprecisio...

Permalink Reply by David Rutten on January 11, 2012 at 7:50am

That's quite a small distance. Meshes are less accurate in Rhino than Nurbs. Nurbs geometry is defined using double-precision-floating-point numbers, whereas meshes use single-precision-floating-point numbers.

Single precision allows for roughly 7~8 decimal places. This may well account for the inaccuracy you are seeing. Perhaps you should model in units that actually make sense, so that the distance between any two relevant points in your model is no less than 0.001 and no more than 10000.0

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Rémy Maurcot on January 11, 2012 at 8:00am

I understood from the following (McNeel), there was a way to program double precision meshes.

I have many problems because of it. Such as working with mesh closed.

But in some cases, I have a double opening of the details of meshes.

Permalink Reply by David Rutten on January 11, 2012 at 12:24pm

Rhino5 has the ability to deal with double precision meshes as well as single precision meshes. However since Grasshopper needs to run on Rhino4 those additions are beyond reach at the moment. Also, I'm not quite sure how easy/possible it is to use double precision everywhere just like that.

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Rémy Maurcot on January 11, 2012 at 10:13am

What should I do admit defeat.

Or get into discussions with the editor?

Permalink Reply by David Rutten on January 11, 2012 at 12:26pm

Using single precision meshes will exacerbate tolerance problems but it shouldn't introduce them. You can try talking about double vs. single meshes on the Rhino forum, see if the modelling guys and gals have any good advice. I don't know enough about this topic to take this much further...

David Rutten

david@mcneel.com

Poprad, Slovakia

Permalink Reply by Rémy Maurcot on January 11, 2012 at 1:33pm

ok thank you so much david,I mention this detail, is based on rhino4 grasshopper! do you think has the release of rhino5 grasshopper would base itself on him? have you a forum to advise me?

Permalink Reply by Rémy Maurcot on December 14, 2012 at 3:29am

I return to this topic to see if the version of grasshopper for rhino 5 meshes are always in single precision. And how can I check?

Thank you in advance.

Permalink Reply by David Rutten on December 15, 2012 at 1:50am

No, Grasshopper does not yet use any double precision meshing. Switching will require a lot of testing and I also don't yet fully understand how double precision meshing is implemented and how it might cause problems.

David Rutten

david@mcneel.com

Poprad, Slovakia

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