User Forum of Software BASEMENT

basemind

User

Registered: 2015-10-28

Posts: 15

BASEmesh Tutorial

Hi,

I've been playing around with QGIS and BASEmesh for a few hours now and am now able to create a mesh with height interpolated nodes (Yay! Not that big achievement, anyhow.).
Having worked with River2D, R-Sim2d and FLO-2D before, however, I still can't get the BASEmesh tool to create a mesh with different grid sizes other than by defining breaklines with different densities of node (maybe based on polygons with corresponding values?).
I also can't see how I am supposed to define boundary conditions (I get that these are related to stringdefs). Am I supposed to define these stringdefs in QGIS/BASEmesh at all? How can I assign different roughness values/soil compositions etc. to grid elements (via stringdefs?)? Are stringdefs kind of like Tags to which I can relate to later (via "string_name" definition in BASEMENT)?

Is there a tutorial showing mesh generation with QGIS/BASEmesh, defining boundary conditions etc. - a BASEMENT for dummies?

Sorry for all the questions, I'm really looking forward to working with this software. I have already read "BASEmesh_manual_v1.2" and I looked into "BASEMENT_v2.5_User" and the contained tutorials. Tutorial Part 2 (p. 199ff), "Hydrodynamics and sediment transport at the river Flaz" is unfortunately referring to SMS as the gridding tool and BASEplane module for calculation, I don't even know however, if BASEplane is a part of BASEMENT (anymore?) or whether it is/was a module.

Kind regards,
a base mind

Last edited by basemind (2015-10-28 16:40:32)

maarnold

Advanced_User

Registered: 2014-09-13

Posts: 28

Re: BASEmesh Tutorial

Hi,

there is a tutorial showing how to generate a mesh with BASEMesh and how to set up a model with BASEMENT:

http://www.basement.ethz.ch/services/Tools/BASEmesh

Just enter the required fields and download the step by step tutorial.

Be aware that in the actual BASEMesh version "Area" under "optional layers" in "quality meshing" has been changed to "Regions".
In the section "Region" you can define a point layer with two attributes:
maximum area: to define the element size of an area in your mesh which is defined by your breaklines and/or model boundary
material index: integer to define the roughness value IN BASEMENT. To every material index value a roughness value can be assigned IN BASEMENT

How to use string defs to define inflow and outflow boundaries is also described in the tutorial above.

hope this helps

mat

basemind

User

Registered: 2015-10-28

Posts: 15

Re: BASEmesh Tutorial

Hi,

thanks for your quick reply! The tutorial did a great job in getting me started; I really appreciate all the approaches: defining materials/grid element sizes/holes via points, the very stringent usage of basement, it's really great!

What almost never works on my first try is meshing, getting that to work is by far the most exhausting step in an overall quite convenient process.

Kind regards