How to increase number of triangles in .stl file?

[sphh]

I created an aerofoil with the help of this wonderful module (Thank you!).

Now I want to export it as a .stl file. That works well, but the tesselation is quite coarse. Because in #128 it is mentioned, that increasing/decreasing the surfaces' delta values would change the resolution, I divided the default delta value by 100. Unfortunately that does not change the number of triangles.

Then I played with the keyword argument vertex_spacing of the export_stl() function. If I set it to a value >1, I get a coarser grid. If I set it to 0.1, I get a geomdl.exceptions.GeomdlException: GEOMDL ERROR: Vertex spacing should be bigger than zero error.

What is the proper way to refine the grid (increase the number of triangles), so that the exported file follows the surface better? Thanks!!

[orbingol]

The delta value needs to change the number of triangles as it changes the number of evaluated points. delta property is stored as a tuple (as you may have already noticed), so dividing a tuple by an integer might not work correctly.

There are also dimensional counterparts of delta, like delta_u, delta_v, and delta_w which can be used to update the number of evaluated points on the specified parametric direction.

You could also play with the sample_size property. It is a wrapper for the delta value but makes more sense to some users.

You could also call reset and then evaluate methods to make sure that the delta/sample size values are updated (this step shouldn't be necessary but let's make sure of it).

[sphh]

I found the mistake: I set the delta value for my surfaces and then I added these surfaces to a SurfaceContainer assuming that the final tessellation of the container takes the delta value for each surface. That was wrong: I have to set the delta value for the SurfaceContainer!

PS: By dividing the delta value by 100 I obviously meant to do it element-wise.