[segersson]

Hi,
I need a utility that extrudes a 2d-mesh with prescribed layer thicknesses. The standard utility extrudeMesh seems to give all layers the same thickness. If I´m not mistaken the layer thickness is calculated using the operator() function in the class linearNormalExtruder. Could one somehow change this function to use prescribed layer thicknesses instead (I'd appriciate any advice)?

Also I will need to extrude several surfaces beginning from different levels in the z-direction (I'm meshing a city block). My plan is to extrude matching meshes for the different surfaces seperatly using a modified extrudeMesh utility, and then stich these meshes together using the standard openFoam mesh utilities (stichMesh?). Is this possible?

Best regards
David

[mattijs]

1) yes, this should be easy. The operator() is indeed the function that generates the points. The layer argument tells you which layer you are generating points for, the surfacePoint argument gives the coordinate of the layer 0 point. Both should tell you where you are so just modify the function to have a non-linear distribution.

2) difficult and might give problems when stitching different blocks. It is easier just to generate a big block and remove cells where there are buildings (using subsetMesh with the '-patch' argument)

[segersson]

Hi,
I want to use extrudeMesh using the -surface argument, i.e. I want to read the 2d-mesh from a file instead of from a patch in an existing mesh. I can not find any example on the format of the surface file, and I have not managed to track down the specification from the PrimitivePatch template-class i Doxygen (gets quite hard to follow for a non-expert C++ programmer...)

Could anybody who have used this functionality post an example or a format-specification for the input file to use with the -surface argument?

Regards
David

[eugene]

Readable surface formats are:

AC3D
GTS
OBJ
OFF
STL
TRI

You can find their definitions on the internet or can check out the source code for the readers here: OpenFOAM/OpenFOAM-1.3/src/triSurface/triSurface/interfaces/

[mattijs]

Try extrude patch of existing case (with sourceRoot/sourceCase/sourcePatch) and look at the file <patch>.smesh it writes.

This is a simple 2D mesh format defined in class faceMesh (faceMesh.H)

[drrbradford]

How can I stop extrudeMesh from removing short edges?

Needless to say, there was supposed to be a middle portion of my mesh. . .