viz(mesh, showfacets = true) crashes old laptop

[Martín D. Maas]

Hi!

I am running some examples where I build a 2d triangle mesh in Meshes.jl, so I thought to give MeshViz a try for visualization. However, trying to plot the triangle mesh crashes my old laptop during precompilation.

The workaround I found is to rely directly on Makie and build a scatter for the vertices and a line plot for the connectivity.

function plotTriMesh(mesh)
    Points = [p.coords for p in mesh.points]
    Simplices = [t.indices for t in mesh.topology.connec]
    scene = Mke.Scene()                                     
    s = Mke.scatter!(scene,Points)  
    lx = Float64[]; ly = Float64[];
    for tri ∈ Simplices
        px = [Points[tri[q]][1] for q in [1:3; 1]]
        py = [Points[tri[q]][2] for q in [1:3; 1]]
        lx = vcat(lx, [px; NaN])
        ly = vcat(ly, [py; NaN])
    end
    Mke.lines!(scene,lx,ly)                              
    return scene
end

This is reasonably fast. Maybe you want to consider having a "fast" visualization for only the boundaries of a mesh, in this fashion.

I don't want to try again using viz(mesh, showfacets = true) because my laptop crashes really badly. This happened to me with Julia 1.7 and now 1.8-rc1.

Best regards,

[Júlio Hoffimann]

Can you please try it without showfacets=true? I should probably change the current behavior and add a check in the code so that new users never try to use this option when the mesh does not have coherent orientation. This option only works if all your triangles or polygons in the mesh are oriented counter-clockwise or clockwise. When you mix the orientation, which is something that Makie doesn't consider, you cannot store the mesh in a half-edge structure and therefore you cannot plot the inner edges efficiently.

If you want to get the same plot that vanilla Makie gives you, you just need to omit the option showfacets=true.

[Martín D. Maas]

Thanks Julio.

Yes, it works that way, but I need to see the triangle boundaries.

I will check my triangles orientation, as I also need the half-edges for the next step in my algorithm.

[Júlio Hoffimann]

This is no longer an issue. We now fix the orientation of polygons for end-users so the option showfacets should always work. This is available in Meshes.jl v0.25.8.

[Júlio Hoffimann]

Can you please try without showfacets=true ? I should probably change the behavior and add a check in the code so that new users never try to use this option when the mesh does not have consistent orientation. This option only works if all your triangles or polygons in the mesh are oriented counter-clockwise or clockwise. When you mix the orientation, which is something that Makie doesn't care, you cannot load the mesh in a half-edge data structure and therefore you cannot plot the inner edges efficiently. So if you want to get the same plot that Makie does just omit the option showfacets Em sex., 29 de jul. de 2022 06:06, Martín D. Maas ***@***.***> escreveu:

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Hi! I am running some examples where I build a 2d triangle mesh in Meshes.jl, so I thought to give MeshViz a try for visualization. However, trying to plot the triangle mesh crashes my old laptop during precompilation. The workaround I found is to rely directly on Makie and build a scatter for the vertices and a line plot for the connectivity. function plotTriMesh(mesh) Points = [p.coords for p in mesh.points] Simplices = [t.indices for t in mesh.topology.connec] scene = Mke.Scene() s = Mke.scatter!(scene,Points) lx = Float64[]; ly = Float64[]; for tri ∈ Simplices px = [Points[tri[q]][1] for q in [1:3; 1]] py = [Points[tri[q]][2] for q in [1:3; 1]] lx = vcat(lx, [px; NaN]) ly = vcat(ly, [py; NaN]) end Mke.lines!(scene,lx,ly) return scene end This is reasonably fast. Maybe you want to consider having a "fast" visualization for only the boundaries of a mesh, in this fashion. I don't want to try again using viz(mesh, showfacets = true) because my laptop crashes really badly. This happened to me with Julia 1.7 and now 1.8-rc1. Best regards, — Reply to this email directly, view it on GitHub <#30>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZQW3PNUYMXNPTKM2EXIIDVWONKPANCNFSM55ABWKWA> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[Martín D. Maas]

Hi Julio, nice work. I think I lost the original example, tough. But my use case was that I needed to see the facets. I ended up using Makie directly, and now I'm working on something else.