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berendsen

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About berendsen

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  1. Thanks - works like a charm! It might be a good idea to include this work flow somewhere on the wiki or the demos ... I think I'll have to decline wrt land use raster - we only have polygon-shape land use data. Except ... we have false colour airial images for the area. Is it possible to automatically classify land use according to the colour bands in a neighbourhood raster? <- somehow this sound more like a GIS exercise, though.
  2. Thanks for the eval licence. I've played around a wee bit with both 11.0 and 11.1.beta2: - As you stated, both version do try and take extra nodes and dangling arc into account. - Scalar Density Paving forces a vertex redistribution along polygon arcs. Is it possible to switch this off? - The max element size in Paving is determined by the max vertex distance of the surrounding polygon. Short of putting a couple of nodes with a certain relax factor in each polygon, is it possible to set another max. element size? <edit> - As the statusbar displays the currently worked on polygon id when generating a mesh, how can I determine the corresponding polygon? Didn't notice that SMS displays the polygon id in the status bar, duh. <\edit> If I manage to create a decent test case, I'll send it over. Thanks again.
  3. Hello All, I'm trying to automatically assign material types to a mesh according to the local land use pattern. So far I've found two ways: 1.) for an existing mesh, manually assign each element one material type 2.) assign the polygons, which are used to bound the auto-generation areas, a material type and then generate the mesh 1. is, especially on larger meshes, very error-prone and time-consuming. 2. is possible, if one can generate the mesh from polygons - which isn't always possible or feasible. Is there a way to assign material types to an existing mesh using a polygon-shape? Thanks for the help and have a good WE, S. Berendsen
  4. Thanks for the quick answer. It does sound like I'll have to take 11.1beta2 for a testdrive ... as the company I'm with is in the EU, is it better to contact a local reseller for a 30 day trail licence or can I just use the form on your webpage? Unluckily I cannot provide you a test case as the data is owned by one of our customers. Using GIS, I basically digitised or adjusted lines to features that I want included in the model. You can easily construct yourself a similar case: Download OpenStreetMap Vector data for an area Create a polygon around the area you want to mesh Try the different mesh creation options (you might have to add some DEM data) A suggestion: The UI in 10.1 for these options is too hidden - it took a good half hour+ from finding references to "scalar paving" in the online help to finding the options dialog for them. I expected to find links for it in the menu-bar or in one of the toolboxes, but apparently you can only reach them via right- or double-click on polygons in the map dialog (nice thinking of being able to set them for each polygon indivually, though). The only suggestion for improvement I can think of currently seems to be a slightly modified paving method: - give a line-shapefile with a table filled with the 'dotting'-distance along a line - given a min and max element size, start dotting: start on the line with the least dotting-distance redistribute resp. create nodes along the line in such a way that the nodes already present are included (it is, I guess, adaptive interpolation) go on to the next-least-distance line and repeat, but with the added restriction that no existing points should be any nearer than the ones already present continue until every line has been dotted ... compute for each point the nearest distance to each neighbour now generate the rest of the points - new distance to old points always about nearest distance of existing points * max. relax factor (sounds like scalar paving) generate mesh elements identify long and thin triangles see whether any added points inside the long & thin triangles can create more regular ones. If so, insert them into the mesh and remesh the addected triangles Hope this can help a wee bit. Thanks, S. Berendsen
  5. Hello All, Short Version: Am currently trying out the different in SMS included automatic mesh generators. Is there a method which does take polygons, points & 'dangling' arcs and then, given min and max size for vertex length, generates a mesh (if necessary, also interpolates vertices on arcs)? Long version: I'm currently using SMS 10.1.11 to generate a mesh and have a couple of days to compare different ways of generating the mesh. Version: SMS 10.1.11 64bit Objective: Want to generate a mesh from lines given in a resp. several shapefile(s). This includes a closed line around the whole area (polygon) and a combination of 'dangleing' (line starts on some polygon border and ends somewhere inside) and closed (forming sub-polygons) lines (resp. feature arcs, once they are converted to Map Data). The 'classic' way is to dot the lines in GIS and combine it with a background raster of a premediated node distance. It works, but does easily result in 'ugly' structures next to given lines. So I tried the different auto-meshing algorithms SMS offers: - none Only useful in the 'classic' case. - patch Fails with "overlapping elements". Seems to be connected to difficulties in generating the polygons from feature arcs (need to run 'generate polygons' several times to convert all areas). - paving Works, put does not offer the ability to set min or max size of elements. Which results in a rather 'ugly' mesh when run on the given feature arcs. When nodes get uniformly respaced along feature arcs, SMS either generates a mesh of uniformly sized elements (which do get computationally expensive) or crashes. - scalar paving density Does not work unless anything 'dangling' is removed beforehand. Then it does construct rather nice meshes of (a predetermined) variable element-size. - existing nodes not tried, but does not sound useful in this case. Is there an algorithm included in SMS which generates meshes like scalar paving density, but takes into account any 'dangleing' arcs and any given points? Thanks for your help, S. Berendsen
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