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Keep elements grouped while remeshing

Pioneer
Pioneer

Hello,

 

I find both groups and the meshing toolbox to be excellent tools in FEMAP. However every time I modify my model and remesh most groups must be re-defined because most elements no longer have the same IDs.

 

Have anyone found a good way to avoid this? I.e. keep the model organized in groups even after re-mesh?

 

Grouping elements on surface or curve etc. does not work in my case as I have big surfaces and only a few hot-spot elements to store in each group.

 

I'm loosing a lot of time re-creating the groups after each mesh-update. Please help!

 

-Kristoffer

5 REPLIES

Re: Keep elements grouped while remeshing

Phenom
Phenom

Hello,

 

Right-click on the group and select "Automatic Add". This'll automatically inject all newly created entities into the group, so nodes and elements created by remeshing as well.

This applies to only one group at a time.

 

AP

Re: Keep elements grouped while remeshing

Pioneer
Pioneer

Thanks, however Automatic Add does'nt help. It adds all new elements into the group. I just want a few hot spot elements in each group and the grouping to stay the same after re-mesh.

 

-K

Re: Keep elements grouped while remeshing

Phenom
Phenom

I see.

 

What characterises your "hot spot elements"?

 

Are they always more or less in the same geometrical location for example? If yes the coordinate-related picking methods can help (in any selection menu, use Pick>{Coordinate, Around Point, Around Vector or Around plane} ).

Or maybe you have a fixed node on the surface you're remeshing, and the "hot-spot" elements are those connected to that node? In which case the connection picking methods can help (Method > {using Node or All Nodes} )

 

These methods exist in the API, thus to really speed things up you could write an API in which you store your "hot-spot" coordinates or regions and the API regenerates groups for each location/region.

Re: Keep elements grouped while remeshing

Legend
Legend

Hi Krisu,

 

You can also try to define a single property for your hot spot elements and then put them in a group created by property. Then after your mesh modif you just have to go to  groups / evaluate and Femap will add all elements you created with the hot spot elements property as the group was created based on property (you can also try the evaluate always). You can try it with a simple model to better understand. 

Group-Evaluate

Hope this helps,

SN 

Seifeddine Naffoussi

Re: Keep elements grouped while remeshing

Pioneer
Pioneer

When remeshing I guess any manually given properties will be overwritten so this would'nt work. Creating an API that find the elements based on e.g. location + orientation might work.

However maybe the fastest way is then:

 

1. Insert a point at the hot spot location on a node

2. Attach the node to the point

3. Go to the group and select "elements using node"

4. Evaluate group after remesh

 

This seems to work well, the only downside is that you cannot exclude elements based on their orientation e.g. if you want only horizontal elements...

 

The same logic goes for loads and constraints - better to attach to an at least quasi-static geometry than to a frequently changing mesh.

 

Thanks,

Kristoffer