<p>Most 3D models are not just collections of points; they’re also the information about how those points are connected. Those are <a href="https://en.wikipedia.org/wiki/Polygon_mesh" rel="nofollow noreferrer">polygon meshes</a>. What you’re describing sounds like a <a href="https://en.wikipedia.org/wiki/Point_cloud" rel="nofollow noreferrer">point cloud</a>, which is what processes like 3D scanning often produce. That article has a “conversion to 3D surfaces” section; if you search for “point cloud meshing” elsewhere you should also find a bunch of information about ways to do this. One new-ish technique worth looking at, which is more robust than a lot of older approaches to the problem: <a href="https://www.dgp.toronto.edu/projects/fast-winding-numbers/" rel="nofollow noreferrer">Fast Winding Numbers for Soups and Clouds</a>.</p>
<p>For OBJ files in particular, polygons are specified with a list of vertices using the <code>f</code> command as described <a href="https://en.wikipedia.org/wiki/Wavefront_.obj_file#Face_elements" rel="nofollow noreferrer">here</a>.</p>

CC BY-SA 4.0
2021-01-21T19:33:03.237Z
2021-01-22T04:31:17.797Z
2021-01-22T04:31:17.797Z
Noah Witherspoon
<p>a 3D model is a collection of points, and basically a 3D software has algorithm to find out how those points connect to make surfaces.</p>
<p>I'm searching for what those algorithms are called, that can use a set of points and properly fill in the dots to create the accurate 3D model from the set of points to create the 3D object intended.</p>
<p>Please mention the name of the algorithm if it's a general approach, if it's file specific then please assume for <code>.obj</code> files. Any links or references would also be highly appreciated.</p>

CC BY-SA 4.0
2021-01-21T21:04:11.457Z
Usually you build the faces manually.
joojaa
CC BY-SA 4.0
2021-01-22T03:05:57.933Z
@joojaa , in .obj files, we can see a list of vertices only, how would a 3D software which imports obj files know how to connect those points?
juztcode
CC BY-SA 4.0
2021-01-22T06:00:53.650Z
no at the end of the obj file there is a list if faces that use the points.
joojaa
CC BY-SA 4.0
2021-01-22T06:24:34.633Z
I figured that earlier and edited the answer below. Thanks for the reply.
juztcode
CC BY-SA 4.0
2021-01-24T14:07:10.850Z
search for rasterization, and you'll find the answer.
Saleh
<opengl>
algorithm that openGL uses to construct 3D surface from vertices
juztcode
# algorithm that openGL uses to construct 3D surface from vertices

(Asked by: username_0 on 2021-01-21)

a 3D model is a collection of points, and basically a 3D software has algorithm to find out how those points connect to make surfaces.

I'm searching for what those algorithms are called, that can use a set of points and properly fill in the dots to create the accurate 3D model from the set of points to create the 3D object intended.

Please mention the name of the algorithm if it's a general approach, if it's file specific then please assume for `.obj` files. Any links or references would also be highly appreciated.

**Tags:** opengl

> **Comments:**
> **username_1**: Usually you build the faces manually.  
> **username_0**: @username_1 , in .obj files, we can see a list of vertices only, how would a 3D software which imports obj files know how to connect those points?  
> **username_1**: no at the end of the obj file there is a list if faces that use the points.  
> **username_0**: I figured that earlier and edited the answer below. Thanks for the reply.  
> **username_2**: search for rasterization, and you'll find the answer.  

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## 1 answers

### Answer by username_3 on 2021-01-21. Score: 2 | Accepted answer

Most 3D models are not just collections of points; they’re also the information about how those points are connected. Those are [polygon meshes](https://en.wikipedia.org/wiki/Polygon_mesh). What you’re describing sounds like a [point cloud](https://en.wikipedia.org/wiki/Point_cloud), which is what processes like 3D scanning often produce. That article has a “conversion to 3D surfaces” section; if you search for “point cloud meshing” elsewhere you should also find a bunch of information about ways to do this. One new-ish technique worth looking at, which is more robust than a lot of older approaches to the problem: [Fast Winding Numbers for Soups and Clouds](https://www.dgp.toronto.edu/projects/fast-winding-numbers/).

For OBJ files in particular, polygons are specified with a list of vertices using the `f` command as described [here](https://en.wikipedia.org/wiki/Wavefront_.obj_file#Face_elements).


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