Problem with meshing when using imported scene

[Augusto Pavon]

Hi everybody!

I've been using I-Simpa for a few days, and I've troubles when trying to work with an imported scene. I've modelled the room attached using AutoCAD, and then converted the file to the different formats that can be used in the programm. 

When I import the scene (in .ply and .3ds formats) with the option "Repair model", and then Run Calculation in any method, programm says "Unable to read the tetrahedalization of the scene mesh file, calculation canceled.", as can be seen in the figure above. When I generate the mesh by its own, without running any calculation, it says everything is ok, and the mesh is generated. So I don´t know what is the problem and can´t fix it.

On the other hand, when importing the scene with the option "Average model remesh", everything goes well when running calculations, but I have the issue that there are looots of surfaces (more than a thousand in total) that are part of each one of the walls, or roof, of my model. In this case, when I try to assignate specific material conditions to the walls, such as absorption coefficient, it turns out to be really hard because I have to define one surface per wall or roof, creating a new group, and this means I've to manually add to each group the numerous surfaces that compose each one. I've understood, from the docs available (https://i-simpa-wiki.readthedocs.io/en/latest/import_options.html) that the parameter Model Solving may help to decide how many little surfaces are part of each wall, but even with the minimum option, the number is really big. 

I would really appreciate any kind of help in the issues I've commented about. Bye!

Augusto

[Nicolas Nico]

Hi,

Yes creating a compatible 3d model for the mesh is quite challenging. Tetgen (mesh program) is expecting a 3d piecewise linear complex model :

http://wias-berlin.de/software/tetgen/1.5/doc/manual/manual002.html#sec%3Aplcs

The main constraints are two segments only can intersect at a common vertex and two facets may intersect only at a union of vertices.

I got good results with this website: https://app.formit.autodesk.com/

best regards

-Nicolas Fortin

[Augusto Pavon]

Thank you very much for your quick response and the information you shared. 

I´ve already done it with the app you recommended and it worked perfectly!

Thanks again. Bye!

Augusto