Opening STL file using stlread function

Hi

This is a line from a code to open binary stl files. My understanding was that the x,y,z vertex coordinates and colours would be stored using this

[x,y,z,c] = stlread(Filename.stl);

I tried to rewrite it as

random.stl=stlread('01_random.stl');

x = random.stl.Points(:,1);

y = random.stl.Points(:,2);

z = random.stl.Points(:,3);

The first line returns

• x - xxxx*3 triangulation
• y-binary
• z xxxx*1 uint16
• c xxxx*1 double

but my code returns

• stl xxxx*3 triangulation
• x,y,z all as xxxx*1 double
• the x,y,z coordinates are stored

Can some explain the first line? What was it meant to do because the values of x,y,z and c are not of the same type.

Answer 1

[T.Nikhil kumar]

Hello Angel,

I understand that you want to know why the outputs of ‘stlread’ function are different from your expectation.

In the first case, the ‘stlread’ function returns:

• ‘TR’ (triangulation object) in ‘x’
• file format in ‘y’(binary/text)
• attributes when the file is binary in ‘z’
• solid identification numbers when the file is text in ‘c’.

It follows the below mentioned syntax:

[TR,fileformat,attributes,solidID] = stlread(filename); 

In the second case, a struct of the name ‘random’ is created which has ‘stl’ as a field. This ‘stl’ field contains the ‘triangulation’ type object that is read from the input file. This ‘triangulation’ object has a ‘Points’ property and each row of this property represents the coordinates of a vertex.

You can refer to the following documentation to understand more about ‘stlread’ function.

https://www.mathworks.com/help/matlab/ref/stlread.html#d126e1556672

Hope this helps!