CAD file format
Uploading your geometry happens via CAD files in the STEP file format. The STEP files are limited to the following specifications:
- Application Protocol (AP) 214: intended for automotive mechanical design process. This is mostly the standard export of your CAD software, but it can be checked and changed in the export options.
- The STEP file is a Part STEP file, it is not an Assembly STEP file. The difference should be clearly marked in your CAD software. If you do have an assembly, export each part separately or contact our support staff.
Uploading your geometry
There are two methods to populate your case with all relevant regions, subregions and boundaries.
The first method is to upload one STEP file which contains all relevant regions, subregions and boundaries. This method can be used as the initial upload of your geometry. After clicking on "upload STEP", select your step file to upload and click on "populate case". The uploading process that now has initiated involves the following steps:
- The contents of your file will be disassembled, meaning that for each body a (sub)region will be created and that surfaces will be assigned as boundaries to regions.
- The geometry will be checked. Bodies and surfaces that do not satisfy these checks (see geometry guidelines) will be given an error on and will not be created.
In the second method, you upload each region, subregion and boundary as a seperate STEP file. A new region can be uploaded by clicking on the "plus" sign next to regions. After selecting the relevant region type, the buttons to upload boundaries and subregions will appear in the region settings window.
These are some of the checks that are performed on the geometries:
On initial CAD upload, the naming of the geometries are handled automatically.
The names of regions and subregions are read from the STEP file and assigned to respective entities.
Due to differences in geometry definition between different CAD softwares, names from some STEP files will not be read. In this case, a default naming format will be used: type number. Where 'type' can be either region, subregion or boundary. The numbering starts with 0. Within each region, the numbering is reset to 0 for subregions and boundaries.
In general, the platform requires input that finds a good balance in the level of detail that is present in the geometry input. Insufficient detail clearly limits the predictive value of simulations, whereas too much detail can hamper separating the important from the non-important.
Here are some guidelines for the level of detail:
- Take care of small features: small features will be captured as well as possible by a simulation, but the more small features, the harder the balance between capturing all of them and capturing the global picture. Leave small features only when they matter.
- Avoid “idealistic” or non-manufacturable” geometry, such as sliver surfaces, cusps, knife-edges, and similar degeneracies.
- Avoid excess realism in the form of geometric details such as embossed or engraved text, fasteners or separate screws.
- When having very thin surfaces or regions, consider simply removing them or replace them by a thermal interface.
- Make sure to give distrinct names to regions, subregions and boundaries.
The geometry is preferably oriented according to XYZ axes. This will improve the quality of the simulation.