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Hi all,

One question that comes up from time to time is how to guarantee that certain points of an outline are retained in a final mesh so I thought I would post an answer here.

There is currently no magic switch to guarantee that a particular node on your outline will be retained by the mesher. However...
By using a combination of automatic outline resampling (achieved by enabling the “Resample Lines Only” on the mesher) and then resampling critical parts of the outline by hand as described below you can achieve this goal.

To resample part of a line you have to use the Line Editing features found on the context menu. (or “Edit->LineSet->”)
To facilitate these operations I suggest you set the Rendering Style to “Lines and Points”

“Split Selected Line” – splits a line at the selected node.
“Resample” – resamples the currently selected line
“Cut” – removes the selected line and places it into the paste buffer
“Append” – appends (joins) the contents of the paste buffer to the currently selected line. This operation will create a closedline if the endpoints are “close”.

Once your outline geometry is satisfactory then run the mesher with the “Resample Outline” option turned off.
This way you can use a different density criteria for outline & soft-line resampling than what you use for the final meshing process.
If you resample soft-lines in this manner, remember to add them as hard-lines to your final meshing process.

Cheers... Martin

If you use a GIS software : Another way is to import in Blue Kenue an outline that has been already resampled. Personally, I use the "densify" function in ArcMap and import the shapefile in Blue Kenue.

Cheers,
S.

Hi
I have a problem: if i resample an outline, the new outline created is not any more a straight line.
Same thing if i resample it in Qgis, i import the resampled line and it is not a straight line!

What do you think of it?



Cheers
Mathieu

Hi

As it was already wrote in the forum on some others topic, this is not a problem of blue kenue but a problem of rounding coordinates!
Shift your data in a local coordinate system near (0,0) and the problem should disappear.

Regards

Very good!
Thank you for your help

Hey!

Above explenation has been quite helpful but I'm still struggling to get the output I want. I'm recreating a mesh used in CGWaves in order to compare a project. I've got the mesh points and the bathymetry, and I've got a closed polygon that I use as an outline. I've used the mesh points as hard points in the mesh generator (I've added a value of 20 in order not to get more points as the hard points would work as a density object). Generating a mesh without resampling the outlines seems to give the perfect result (exactly covering the same mesh points as the mesh I wanted to recreate). The problem however is, that when I distract a conlim file from this mesh, the boundary points don't only include the points on the outline, but link some random points. I then can't run it in ARTEMIS.

When I do resample the outline, the conlim file seems correct and is usable in ARTMIS. BUT, I have to increase the density a lot in order to let it follow the outline neatly, but that influences the density in the whole mesh (which I at some points want to be bigger). Solution could be resampling the outlines seperately like you explain in this topic, but I've tried and then the conlim file gives weird and unusable results again.

Would anyone know how to either get a better mesh when resampling the outline, or get a better conlim file after not resampling the outline?

I've added a folder with a document including some screenshots that show the different results, the two different meshes created and the hardpoints and outline.

Any suggestions would be very much appreciated!

Attachments don't seem to be easy..

This is only the document with the images, the rest doesn't seem to upload, even though I zipped the folder (?)

Hi,

I can't tell what the issue is from the posted images.

I'll have to see your actual data. Perhaps the zip file is too large. Is there an ftp site where you could deposit the files?

Cheers... Martin

I uploaded them on google drives. Hope that works!

drive.google.com/folderview?id=0B7wV1Jf3...RWV9HdXc&usp=sharing

Thanks a lot!