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Hi Martin,

to create very large meshes I use a lot of polygons to mark different density of mesh in different areas. This works very well and with the edge growth ratio I can control the transition between two different densities. However I noticed that this edge growth ratio is not applied on the outline, leaving me a very bad local meshing result. I also noticed it is in the tutorial as well but since there the difference between the two densities is not so big, this problem is small.
1. Is there a good way to work around this problem?
2. Is this something that you might consider improving in a next release?

I added a figure as an example

Kind regards,
Sven

Hello Sven

did you use the "resample outline" option before launcing the mesh generation?
This works pretty well for my applications. To be verified (with Martin)!

Cheers
Riadh ATA

Hi Riadh,

yes I use this option, but I think it works before the edge growth ratio is taken into account, because BK resamples the outline strictly in the density that is given for that location. There is no transition on the outline between two neighbouring different densities.

Sven

Hi Sven
You're right, the resampling is only managed by the density and it doesn't take in account the edge growth ratio.
One possibility I usually use to solve such problem is to build a larger area and triangulate it. Then I build a first mesh with my criterion and also the hardlines. I extract the edgelength of this mesh and use it as a final criterion of density.
With this method, the resample of outline is consistent with your criterion and also with the edge growth ratio

Hope this helps

Hello Sven

In that case, you need to resample your outlines (or boundary) with a delta less our equal to your internal density.
I guess that this will not ensure automatically a nice transition from elements on the boundary to the internal ones, however, it could improve the mesh quality.
Meanwhile, it is better that the growth ratio needs to be applied for boundary as well, as you have proposed.

Riadh

Riadh and Christophe,

thanks for the quick replies. Christophe, I will try your solution. It will work I'm sure, but it will be labour intensive as I have like 50 density polygons.
I'm making a new 3D model for the Scheldt estuary that will be coupled with Delwaq and I hope Sisyphe. I'm looking forward to present it at the TUC in Grenoble!

Thanks,
Sven

Hi Sven,

Unfortunately, as previously posted, this is a current limitation of the mesher. I had hoped to finish implementing this functionality but it seems like there is always something else to do.

Anway, Christophes suggestion is what I would recommend at this point and is indeed what we often do here.

The other approach I like is to use is to develop the mesh in 2 stages.

1. Supply the density as a pointSet and enable the "Resample Lines Only" option. (local densities are interpolated from the pointSet(s) using inverse distance weighting so you have nice smooth transitions)

2. Then use the resulting "Resampled Outline" (and "Resampled Softlines" if applicable) as a fixed outline (turn off "Resample Outline") and "hardLines" for the final mesh.

Hope this helps... Martin

Hi Martin,

it's good to hear that at least this is an issue to be implemented somewhere in the future. It will only make Blue Kenue more awesome!

For now I can really try your suggestions. Like the one that Christophe suggested, this one can also really solve my problem.

Thanks a lot

Sven

Hi ;
Thank you for all of your suggestions
I tried all of them to solve this problem ,
I Used to resample the outline with an equal delta of my internal density then, I generated a new mesh .
But I found that the anomaly of the mesh still exists and there is a deformation of the outline which takes the same shape like the anomali of the mesh like this:



please there is any recommandation ?

cheers Ritta

Hi Ritta,

what you can try is to draw a polygon outside your outline and use this as a new outline to generate a bigger mesh, but with the same density as you want in your first mesh.
Then you add the new bigger mesh to a mesh generator as density map and add your first outline as outline. Then you resample outline and resample lines only. This mesh generator will then only resample your outline.
You can then replace the bigger outline in your first mesh generator with this resampled one and then make sure you don't resample only anymore.

Hope this is a little clear to you if not let me know and I try to explain more elaborate.

Sven