implement export VTK

Project.toml

@@ -11,6 +11,7 @@ StaticArrays = "90137ffa-7385-5640-81b9-e52037218182"
 Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 Suppressor = "fd094767-a336-5f1f-9728-57cf17d0bbfb"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
+WriteVTK = "64499a7a-5c06-52f2-abe2-ccb03c286192"
 
 [weakdeps]
 PlotlyJS = "f0f68f2c-4968-5e81-91da-67840de0976a"

docs/Project.toml

@@ -8,3 +8,4 @@ Plots = "91a5bcdd-55d7-5caf-9e0b-520d859cae80"
 PlotlyBase = "a03496cd-edff-5a9b-9e67-9cda94a718b5"
 PlotlyKaleido = "f2990250-8cf9-495f-b13a-cce12b45703c"
 WebIO = "0f1e0344-ec1d-5b48-a673-e5cf874b6c29"
+WriteVTK = "64499a7a-5c06-52f2-abe2-ccb03c286192"

docs/src/fileio.md

@@ -51,4 +51,50 @@ savefig(t, "sphere.html"); nothing # hide
 
 ```@raw html
 <object data="../sphere.html" type="text/html"  style="width:100%;height:50vh;"> </object>
-```
+```
+
+
+## VTK Files (ParaView)
+
+To display surfaces in [ParaView](https://www.paraview.org/) the function [`saveVtk`](@ref saveVtk) is provided. 
+It converts the surface to an unstructured grid and exports a .vtu file which can be opened by ParaView.
+
+```@example vtk
+using NURBS, FileIO
+Patches = load("assets/torus.stp")
+
+saveVtk("path/filename", Patches; resolution=0.01) # filename without extension
+nothing # hide
+```
+
+```@raw html
+<div align="center">
+<img src="../assets/paraview.png" width="750"/>
+</div>
+<br/>
+```
+
+
+
+To add color information the function [`vtk`](@ref NURBS.vtk) can be used together with the [WriteVKT.jl](https://juliavtk.github.io/WriteVTK.jl/stable/) package.
+To this end, the color values at the four corner points of each cell have to be provided in a Vector.
+
+```@example vtk
+using NURBS, FileIO, WriteVTK
+Patches = load("assets/torus.stp")
+
+cellV, x, y, z = NURBS.vtk(Patches, 0.01)
+
+vtk_grid("/home/bernd/Dokumente/vtk/cells", x, y, z, cellV) do vtk
+    vtk["dataName"] = 2 * x + y
+end
+nothing # hide
+```
+
+```@raw html
+<div align="center">
+<img src="../assets/paraviewCol.png" width="750"/>
+</div>
+<br/>
+```
+

docs/src/meshes.md

@@ -53,7 +53,7 @@ nothing # hide
 ```
 
 !!! tip
-    To determine all connectivity information, the [`Connectivity`](@ref Connectivity) function can be used, which returns a struct containing the interface vector, the patchwise vectors and the Bezier adjacency:
+    To determine all connectivity information, the [`Connectivity`](@ref NURBS.Connectivity) function can be used, which returns a struct containing the interface vector, the patchwise vectors and the Bezier adjacency:
 
     ```@example meshes
     using NURBS

docs/src/trafos.md

@@ -19,7 +19,7 @@ nothing # hide
 
 ## Translating
 
-To translate a curve or a surface, the functions [`translate`](@ref translate) and [`translate!`](@ref translate!) are provided.
+To translate a curve or a surface, the functions [`translate`](@ref NURBS.translate) and [`translate!`](@ref NURBS.translate!) are provided.
 
 ```@example trafos
 using NURBS, StaticArrays
@@ -32,7 +32,7 @@ nothing # hide
 
 ## Rotating
 
-To rotate a curve or a surface around a rotation axis by a given angle, the functions [`rotate`](@ref rotate) and [`rotate!`](@ref rotate!) are provided.
+To rotate a curve or a surface around a rotation axis by a given angle, the functions [`rotate`](@ref NURBS.rotate) and [`rotate!`](@ref NURBS.rotate!) are provided.
 
 !!! tip
     The rotation axis is normalized by the rotate functions.

ext/plotting.jl

@@ -167,7 +167,7 @@ end
 Plot multipatch geometry.
 """
 function NURBS.plotPatches(
-    Patches; mesh=[], pos=[], plotControlPoints=true, localVertices=false, patchID=false, enforceRatio=true, resolution=0.05
+    Patches; mesh=[], pos=[], plotControlPoints=true, localVertices=false, patchID=false, enforceRatio=true, resolution=0.05, color=[]
 )
 
     uEvalpoints = collect(0:resolution:1.0)
@@ -193,7 +193,12 @@ function NURBS.plotPatches(
             )
         else
             maxi, trace = plotSurface(
-                S; returnTrace=true, surfaceColor=col[ind] * ones(length(uEvalpoints), length(vEvalpoints)), cmin=1, cmax=maximum(col)
+                S;
+                returnTrace=true,
+                surfaceColor=col[ind] * ones(length(uEvalpoints), length(vEvalpoints)),
+                cmin=1,
+                cmax=maximum(col),
+                #S; returnTrace=true, surfaceColor=color[ind], cmin=0, cmax=2
             )
         end
         [push!(traces, trace[i]) for i in eachindex(trace)]

src/NURBS.jl

@@ -7,6 +7,7 @@ using StaticArrays
 using Suppressor
 using FileIO
 using UUIDs
+using WriteVTK
 
 
 
@@ -25,7 +26,7 @@ export insertKnot!, insertKnot
 export coarsen, refine # NOTE: split is an extension of Base.split, i.e., it is publicly available without export
 export removeKnot!, removeKnot, removeKnotU, removeKnotV
 
-export readMultipatch, readStep
+export readMultipatch, readStep, saveVtk
 export generateKnotVec, numBasisFunctions, spanRanges
 export greville, anchors
 export scale, scale!
@@ -66,6 +67,7 @@ include("fundamentalOperations/knotRemoval.jl")
 include("utils.jl")
 include("fileIO/multipatch.jl")
 include("fileIO/step.jl")
+include("fileIO/vtk.jl")
 include("fileIO/fileIO.jl")
 
 function __init__() # locally initialize file formats for FileIO load and save functions

src/connectivity/bezierMesh.jl

@@ -12,6 +12,14 @@ function cellCart2LinTruncated(cellU, cellV, pInd, cU, cV)
     return cellCart2Lin(cellU, cellV, pInd, cU, cV)
 end
 
+function cellLin2Cart(cell, cU, cV)
+
+    pInd, rem = divrem(cell - 1, cU * cV)
+    cellU, cellV = divrem(rem, cV)
+
+    return pInd + 1, cellU + 1, cellV + 1
+end
+
 
 # for a single patch cU ≠ cV is ok, for multipatch cU = cV is assumed
 function bezierAdjacency(interfaces, commonVtxs, cU, cV, nP)

src/fileIO/vtk.jl

@@ -0,0 +1,71 @@
+
+function coordis(S)
+    x = [S[i, j][1] for i in eachindex(S[:, 1]), j in eachindex(S[1, :])]
+    y = [S[i, j][2] for i in eachindex(S[:, 1]), j in eachindex(S[1, :])]
+    z = [S[i, j][3] for i in eachindex(S[:, 1]), j in eachindex(S[1, :])]
+
+    return x[:], y[:], z[:]
+end
+
+
+"""
+    vtk(patches, resolution=0.01)
+
+Prepare the patches to be displayed by Paraview: 
+
+The output can be written to the VTK format using the WriteVTK.jl package.
+
+using WriteVTK
+
+vtk_grid("path/filename", x, y, z, cellV) do vtk
+end
+"""
+function vtk(patches, resolution=0.01)
+
+    uEvalpoints = collect(0:resolution:1.0)
+    vEvalpoints = collect(0:resolution:1.0)
+
+    Nv = length(vEvalpoints)
+    Nu = length(uEvalpoints)
+    Nc = length(patches)
+
+    cellV = typeof(MeshCell(VTKCellTypes.VTK_QUAD, [2, 4, 3, 5]))[]
+    for cell in 0:(Nc - 1)
+        for j in 0:(Nu - 2), i in 1:(Nv - 1)
+            ind = j * Nv + i + cell * Nu * Nv
+            push!(cellV, MeshCell(VTKCellTypes.VTK_QUAD, [ind + Nv, ind + Nv + 1, ind + 1, ind]))
+        end
+    end
+
+    x = Vector{Float64}()
+    y = Vector{Float64}()
+    z = Vector{Float64}()
+
+    for (_, patch) in enumerate(patches)
+
+        S = patch(uEvalpoints, vEvalpoints)'
+        xs, ys, zs = coordis(S)
+
+        append!(x, xs)
+        append!(y, ys)
+        append!(z, zs)
+    end
+
+    return cellV, x, y, z
+end
+
+
+"""
+    saveVtk(filename::String, patches; resolution=0.01)
+
+Save as an unstructured grid in a .vtu file to be displayed by ParaView.
+"""
+function saveVtk(filename::String, patches; resolution=0.01)
+
+    cellV, x, y, z = vtk(patches, resolution)
+
+    vtk_grid(filename, x, y, z, cellV) do vtk
+    end
+
+    return nothing
+end

test/runtests.jl

@@ -8,7 +8,7 @@ using PlotlyJS
 using FileIO
 
 # --- testsets
-@testset "Testing NURBS functionality" begin
+@testset verbose = true "Testing NURBS functionality" begin
 
     @testset "Bases" begin
         include("bases.jl")

test/utils.jl

@@ -143,6 +143,10 @@ end
 
     Patches = readStep("assets/sphere.stp")
     @test length(Patches) == 6
+
+
+    # --- .vtk files
+    @test_nowarn Patches = saveVtk("test", Patches; resolution=0.02)
 end
 
 @testset "Plotting" begin