Getting 3D shapes without illumination

Specific Domains Visualization
1

I am plotting with GLMakie my own 3D solids by defining GeometryBasics.faces(...) and GeometryBasics.coordinates(...) for each type. Then I plot the solids using a code like this:

   m = GeometryBasics.mesh(solid)
   points = GeometryBasics.coordinates(m)
   faces  = GeometryBasics.faces(m)
   map!(c -> c * t, points, points)           # apply some transformation to the points
   m = GeometryBasics.Mesh(points, faces)     # remake a mesh with the moved points
   mesh!(s, m, color=color, transparency=true, visible=true)

It works but I get the 3D shapes without illumination. Like this:
Screen Shot 2023-06-09 at 11.47.42

Does anybody know what I should do to get a more realistic display of my solids?

2

This happens when you have missing or inverted normals. I always forget what the command is to get them but that might help you google it :slight_smile:

3

This should work:

m = GeometryBasics.normal_mesh(solid)
points = GeometryBasics.coordinates(m)
faces = GeometryBasics.faces(m)
map!(c -> c * 0.1, points, points)           # apply some transformation to the points
m = GeometryBasics.Mesh(meta(points; normals=normals(m), faces))
4

Thanks, but it does not work. Perhaps I am missing something else.
I am not able to construct a normal_mesh with my shapes, and therefore the normals(m) returns nothing.
I was able to construct a mesh because I had the following functions defined I guess:

    function GeometryBasics.Tesselation(s::G4VSolid, nvertices::NTuple{N,<:Integer}) where N
        return Tesselation{3,Float64,typeof(s),N}(s, Int.(nvertices))
    end
    GeometryBasics.mesh(s::G4VSolid) = GeometryBasics.mesh(Tesselation(s, 64), facetype=typeof(first(GeometryBasics.faces(s))))

How can I do the equivalent for normal_mesh? BTW, I do not find any documentation on normal_mesh.

5

I see…

That’s not really what you should overload - sorry, this is badly documented, and don’t have time right now to document it :wink: Have to look at e.g. Sphere to see what to overload.

Anyways, the easiest solution to get things working is to just do this:

m = GeometryBasics.Mesh(meta(points; normals=normals(points, faces), faces))
6

Thanks very much. It works if I put the parenthesis in the right position

GeometryBasics.Mesh(meta(points; normals=normals(points, faces)), faces)

I will have a look at the Sphere.