User Forum of Software BASEMENT / Output

Qsed output inside the mesh

dummy@example.com (Irene Samora) — Thu, 30 Oct 2025 16:50:57 +0000

Hello,
This is an old question from 2021, but is it possible to get a reply to the last post? I would like to understand how is Qsed node-based calculated.
I need to estimate the bedload that passes through a few sections of an old model but I do not have any stringdefs at these locations and I cannot afford to rerun it (too long, too much time, old version etc).
Thank you in advance

Export As Raster

dummy@example.com (Matteo Facchini) — Mon, 18 Aug 2025 15:20:38 +0000

you should first calculate the max with the mesh calculator, using the max_aggr function.
this will add a dataset to your results, afterwards you can rasterize it

anyway, i suggest you to use the flood module, and then rasterize that dataset

Basement HPC v4.1 / Parcial results

dummy@example.com (DiegoB) — Sun, 16 Jun 2024 17:46:24 +0000

Hello everybody,
I wonder if it is possible to generate a .xdmf file for Visualization from parcial results while the Simulation is still running.
Thank you very much in advance
Kind regards,
Diego B

stringdef_history

dummy@example.com (Christian_Juffinger) — Thu, 23 May 2024 08:19:52 +0000

Hello Matteo!
I would be interested to know how exactly this ‘average value’ is calculated. I can't find it anywhere in the manual... how does Baseplane interpolate the values calculated on an element basis to the nodes and how is an average value calculated. Thank you for your answer.

Re-running a simulation from Basement v.2.8.2 to Basement v4.0.2

dummy@example.com (Matteo Facchini) — Fri, 19 Jan 2024 11:22:04 +0000

Hi,
try to open the results with ParaView and see what happens.
Possible explanation for the "could not read mesh dataset" could be:

wrong header in the .xdmf file as reported somewhere else in the forum
wrong path pointing to the mesh in the .xdmf file
something wrong in the simulation (you can see it with paraview)

Hope this helps

How to visualize a time variant profile animation in a 2d model

dummy@example.com (Stephan Kammerer) — Tue, 05 Oct 2021 14:24:22 +0000

Unfortunately its not possible to directly export amimations from Crayfish 2D Plot. You can export individual timesteps of datasets along cross sections or at point locations of your mesh.
However it is possible to use Python scripting in order to export all available timesteps for animations automatically. For QGIS 2.18 you can find some example scripts on this in the plugin folder located under: C:\Users\username\.qgis2\python\plugins\crayfish\examples

BASEvis can not work

dummy@example.com (Alyssa) — Mon, 16 Aug 2021 18:48:43 +0000

I have the same error. Recently installed QGIS 3.16.9 and am using Basement 2.8.1.

thanks for anyone who has a solution

Alyssa

output transport capacity

dummy@example.com (Matthias Bürgler) — Wed, 20 May 2020 09:38:32 +0000

The transport capacity is not an available output for 2D simulations, as far as I know. You can generate outputs of the transported sediment (bedload_vec) on nodes or elements, though. Also with "sediment_sum" you can track the total sediment that has eroded or deposited in a cell.

Best regards
Matthias

Convert Map output to raster and Map output of velocity

dummy@example.com (Matteo Facchini) — Mon, 20 Apr 2020 16:00:35 +0000

I kindly ask Mathias to move this thread back to BASEMENT 2.8.
Sorry again!

QGIS fails to read *.sol files

dummy@example.com (Marulke) — Thu, 12 Mar 2020 13:35:27 +0000

Thanks Matthias,
your answer solved the problem.

Best regards,
Marsulke

negativ velocity

dummy@example.com (Matthias Bürgler) — Thu, 23 Jan 2020 13:06:09 +0000

Hi Dominik
It is correct that the x- and y-components of the depth averaged flow velocity are components of the velocity vector u. The flow direction is determined by the direction of the velocity vector in the cartesian x-y-coordinate system. The coordinate system is determined by your mesh and not "set" within BASEMENT. Therefore also the alignment with a geographic coordinate system depends on your mesh.

I suggest to have a look at the equations you are solving with BASEMENT in the Reference Manual, e.g. under Sections "1.1.2 Shallow Water Equations" and "2.2.3 Shallow Water Equations". Figure 2.22 could also be helpful for the understanding.

Best regards
Matthias

Hydraulic time step

dummy@example.com (sterrier) — Mon, 20 Jan 2020 15:29:43 +0000

Dear all,

My Basement 2.8 R5771 model takes a long time to compute, and I’m looking into the hydraulic time step in order to understand why. In the “balance” output, the time step varies in the range 0.004 - 0.168 s. The output also gives the limiting element and edge. If I manually estimate the CFL number at that edge (velocity of ~0 m/s, water depth of ~50 m and edge length of ~20 m), it gives a maximum time step of 0.9 s according to equation 2.221 of the reference manual. So much larger than the one indicated in the balance output, which lets me think there might be a way to optimize the model.

I thought setting output_time_step = 0 for balance would show me the results for all time steps performed during a simulation to understand what is happening. But it doesn’t, it sets the hydraulic time step to 0.001 (default minimum_time_step I suppose). Then I discovered that changing the output time step (console or balance) can significantly change (double or half) the hydraulic time step. For example, in the tutorial files “Flaz-01-hydraulic-stationary”, changing the console time step from 100 to 10 changes the hydraulic time step in the balance output from 0.007 s to 0.024 s. However the total simulation time does not vary greatly, which raises doubts about what is the hydraulic time step actually used.

Is there a way to show the list of all hydraulic time steps performed during a simulation?
And is it normal that the output time step influences the hydraulic time step?

Best regards,

Stéphane

Transverse components of velocities.

dummy@example.com (Matthias Bürgler) — Mon, 17 Jun 2019 07:00:06 +0000

Hi Anna
I think the easiest way is to use output type element_centered and with "velocity" and compute the averaged ux and uy over the boundary from the boundary elements during the post-processing.
Best regards
Matthias

problem opening vtk (precision)

dummy@example.com (Matteo Facchini) — Tue, 20 Nov 2018 10:40:42 +0000

Dear all,

I had a problem in opening a vtk results file with paraview and I found out that it was related to the precision of the vtk.

In fact, in the first few lines there was an improbable -3.643557e-40 among the coordinates (it was a z coordinate of a point), which was causing troubles. To solve the problem, I substitute it with 0.

I suggest to put a threshold in the output, i.e. if the level is below say 1e-14 it should become automatically 0.

Cheers,

Matteo

How to obtain any cross-section flow discharge history?

dummy@example.com (Matteo Facchini) — Mon, 12 Nov 2018 15:19:08 +0000

Hi Wei,

first of all I suggest you to go through the manual, where you could find the information you are looking for.

If you do that, you might want to look for the stringdef_history or edge_history in the outputs.

Best,

Matteo