Export membrane from Forten2Caedium


I would like to make a CFD analysis with Caedium on my membrane exported from Ixforten.
So as I have already done an example with PV panels on the roof in Caedium I found out that all elements has to be connected to environment cube where I define inlet, outlet etc.
My membrane is on concrete columns but when I import my model in Caedium it imports only membrane surface.
How it is suppose to be done? Export from Forten? Make further steps in Caedium, cube around membrane and something under membrane that connects environment cube with membrane? Is it possible to get any example with membranes in Caedium?


best regards

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Try a simple 2-sided membrane case

Before considering a complex membrane case, I suggest you try a simple membrane case as outlined in the comment "First try a simple 2-sided case".

You don't want anything touching the membrane. However, it has to be subtracted from the flow volume. For more details see "Topology Operations".

If it is only the membrane that is exported from ixForten then you will need to recreate the blocks in Caedium.

Once you have the flow results for a membrane, you can export the membrane as Alias/Wavefront (.obj) from Caedium. Ensure only the membrane is visible and is flat shaded. Plot the surface Cp data and export the plot as Comma Separated Values (.csv). For more help contact ixForten.

Can I just repeat some of the

Can I just repeat some of the things you said, just to check if I got it right?

Basically an .obj file is exported from ixForten 4000.
Then membrane blocks (fem triangles?) are recreated in Caedium, an CFD analysis was completed. Then membrane roof was again exported as .obj, but this time imported into ixForten 4000.
Also Cp data was exported as .csv and imported into ixForten 4000 too.

That is it?

Why do we need to export the .obj file from the Caedium for the second time?
When we already have the results from the Cp.csv file?
Because second .obj file contains the mesh data of the surface?

Thank you for the reply.


Just to clarify:

  • "...Cp data was exported as .csv..." from a Caedium plot not a surface color map
  • "..second .obj file contains the mesh data of the surface?", exactly - Caedium will generate and solve for a different mesh than the one originally imported from ixForten 4000

Thank you for the reply once

Thank you for the reply once again Symscape.

Is there any tutorial on how to plot the surface Cp data?

Same as plotting data on an edge

You use the same technique as to plot data on an edge:

  • Drag and drop Scalar Fields->Cp from the Physics Tool Palette onto the membrane face and its shadow face, then select XY Plot
  • Make sure the plot is selected then click File->Export and select Plot Series (*.csv) as the file type

For more details on plots see "Fluid Flow Around a Sphere: Theory Comparison".

Caedium Membrane Tutorials

For detailed explanations on how to create the membrane flow volume and perform a CFD simulation around a membrane see:

Other Membrane Shape examples

I have reviewed your Double Side Membrane example for CFD analysis. Do you have other type of membrane shapes examples available? I am interested in seeing Caedium CFD analysis to generate Cp data for Saddle Span shape, Hypar shape, Ridge Valley shape, Arch supported shape. This Double Size High-point membrane structure is too simple. For complex curved tensile fabric surface, I would like to compare the CFD results with some wind tunnel testing results for these shapes.


Caedium Professional Free Trial for your validation

Your best option is to request a Caedium Professional free trial to perform the validation of your specific geometry against your test results.