How can I load (many!) points from file, and display them in 3D including color?

Hi,

I'm new to MATLAB

I need to upload many points from a file (up to 25 milion points, but about 15 milion points will also be enough) and display them in 3d space including the option to move them in all dicertions. I also want (if it's possible) to determine the Color of each point.

I create the input file by myself, so it's easy for me to change the format of this file to any format that Matlab can read.

For example it can be a simple text file in the format:

7850, 5394, 6240, 0x22578C

5172, 2958, 1852, 0x72B5A4

397, 1450, 42, 0xB4FC7A

.....

.....

where each line is a pixel: x, y, z, Color in RGB.

I can also create a binary file (for example: "InputPoints.bin") with the points data if it's easier for the Matlab to read.

So, I need to load all the points from my input file, and to show them as color points in a 3d space.

If adding color for each point is a problem, then for now points without a color will also be "OK", but points with color will be much better for what I need.

Please advice,

Thanks!

Answer 1

[dpb]

See

doc scatter3

ML can read whatever datafile format you wish to use...for such large data a stream file would be obvious choice.

While 25E6 points is only roughly 300 in each of the three directions, even a large monitor may have only 2560x1440 pixels so even if each dot is represented by one pixel there's ~10X more points than pixels to display. In short, you'll likely just have a blob.

I don't know where ML will break down (or if it will) with number of points--the new(ish) scatter3 is a single object but how many internal handles it has to create I dunno...

[MathLab User]

Thanks,

I'll check it, but does 'scatter3' allows me to load the points from a file?

Does it let me choose my own color for each one of the points that are loaded from this file?

[dpb]

Reading data is independent from plotting...there are a "veritable plethora" of options available; read the "Getting Started" doc links "Data Import and Analysis"

https://www.mathworks.com/help/matlab/data-import-and-export.html

The examples for scatter3 in the documentation include all you need to know to do what you've asked and more... https://www.mathworks.com/help/matlab/ref/scatter3.html?searchHighlight=scatter3&s_tid=doc_srchtitle#btr5_il-1

Doesn't look/sound like you've done any exploratory work or reading at all to speak of...