performance tuning - Fast way to export large amount of data in "Table" format

I have about a million 3D points, say

data = Table[{1. x, 1. y, 0.}, {x, 1000}, {y, 10^3}]~Flatten~1;

I want to visualize them, but Graphics3D@Point@data or ListPointPlot3D@data are too slow.

MeshLab or CloudCompare can do it, but I need to export it in some way to get it there. It can read ".txt" files with the "Table" format that Mathematica produces, but that takes a very long time to write:

AbsoluteTiming@Export["test 1mio points.txt", data, "Table"]

{23.9979, "test 1mio points.txt"}

CSV file writing is not much faster. It doesn't look like there is a general bottleneck in converting numbers to text format, as '.m' is written quite quickly:

AbsoluteTiming@Export["test 1mio points.m", data]

{1.92666, "test 1mio points.m"}

but MeshLab cannot handle it.

Any alternatives? Is there a way I can convert a list of points to a GraphicsComplex or Mesh or so and then export that in some format (that might be faster).

Answer

I started working on a package and LinkedLibrary achieving significant speedups with this job:

data = Table[{1. x, 1. y, 0.}, {x, 1000}, {y, 10^3}]~Flatten~1;
<< ExportTable`

AbsoluteTiming@ExportTable["test 1mio points.txt", data]

{0.0381513, Null}

You can find it here: https://github.com/Masterxilo/ExportTable

Comments

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