Out of Memory due to Building Polygons

Hello

I'm trying to build a mesh in Mesh Generator (area 3km^2, max. element surface 5^2). I also added building footprints which sometimes have a lot of vertices. When I want to generate the mesh, even with a max. element area of 100m^2, the generator runs out of memory (16GB RAM is installed). What can I do for still getting a mesh?

Help is much appreciated. Thank you!

Best, Sam

Hi Sam,

I would recommend following:

1. Reduce number of vertices: you can do this via GIS -> Generalize function.
Use a small tolerance, then ArcGIS will keep the general geometry but will remove all vertices on straight line segments.

2. Reduce Number of polygons if possible. GIS offer here an aggregate function.

3. Sometimes it helps to simplify complex polygons and divide them into smaller simpler polygons.

4. It could also help to
a) export all arcs as XYZ
b) import to a GIS
c) reimport from GIS via XYZ into MIKE21FM.
MIKE21Fm then likely reorganizes the lines and polygons. This leads to a much better performance and could help to generate your mesh.

Bests
Christian

Hi Christian,

Thank you for your reply.

Indeed the simplification of the polygons helped a lot. The import-export method you described sounds very interesting to me, I'll be trying it next time if I still get errors.
I discovered that my outer domain boundary followed the raster pixels (raster to feature convertion) which lead to the creation of numerous tiny triangles. This made the triangulation fail or at least it took a lot of memory. Then I also included a minimum distance (buffer and clip) between the outer domain boundary and the building polygons to make sure that there are no overlaps. With this I could generate the desired mesh and this question can be closed.

If I may ask, do you have an idea for my question about the break lines in the mesh generator (see general topics, "import of break lines")?

Best regards, Sam

Hi Sam,

when you use the tool Raster tp Polygon you have the possibility to simplify the polygons.
You should always check this option.

This generates much smaller polygons which significant less vertices.

Bests Christian.