Elmer Discussion Forum

Hi Mark

If there is no existing import format it may just be a few hours of work to add one. Usually this goes in the following steps

1) Explore the output formats of the mesh generator and see what could be useful starting point. Often there is no documentation but of course better if there is.
2) Make several minimal examples featuring different elementtypes
3) Write a parser such that it can deal with the small examples.
4) Test it with real examples

Of these 1), 2) and 4) can be done by an interested user. Time permitting doing 3) should not be too much for the development team. However, it is essential that there is a good format to work on. For Femap this is probably the case as it is intended to be a general purpose mesh generator.

-Peter

Hello all,

Can I use the output files from Triangle (https://www.cs.cmu.edu/~quake/triangle.html) witth Elmer?

Hello,

If you open a command window and enter 'elmergrid', it will output help text. Look for input formats, and you will find format 11 is for Triangle.

run elmergrid like this:

elmergrid 11 2 filename -autoclean

and it should generate the Elmer mesh files.

Rich.

Hello,

Thanks. Code is running but files are not being created.

it finishes like this:
LoadTriangleInput: elem i=21131 j=21130
LoadTriangleInput: elem i=21132 j=21131
Loading nodes from file trafo_aniso_lin.poly
Creating an inverse topology of the finite element mesh

Hello,

I get the same result. Do you have another way to check that the input files are valid?

Attached are two examples of Triangle format that Elmergrid can convert properly.

Rich.

It is probably version issues. Both codes are old. Triangle seems to have been abandoned the latest version 1.6 was 2005. ElmerGrid started 1995. It is not likely that ElmerGrid kept up with Triangle versions since they quite in 2005. I think it is probably a mismatch in format due to version releases.

I think the code for *.poly generation file is broken.

Hi,

Is there some flag to force indexing to start from 1. The sample seems to have C-style indexing. It is not hard to code but if it is a flag in Triangle maybe not worth the effort.

The fresh "devel" has some improved diagnostics.

-Peter

Hi,

Just added the offset but it seems that the .poly file is indeed broken. The old logic does not make sense in interpreting this one. I can change the code, but what is the logic that covers both of the cases?

-Peter

Is there a way to do the conversion without the poly file?
Regarding my broken poly file, best is for me to try fixing it.