I don't know of any easy way to accomplish what you want to do without doing some programming to read your surface points. It is my hope someone else can provide an easier way. The way I did it was to come up with a smooth/rough factor for point clouds. It will work better if your coordinates for the surface points are evenly spaced. What I did was to write a program to apply a custom filter to each point. For this to work apply a set radius to each point. All points within this set radius, a plane was fit. From this fit plane a normal was calculated. If the plane fit associated to all the points within the radius was good it this was smooth and if the fit was bad then it was rough. A histogram was made from the smooth/rough factor and then a threshold could be set to differentiate smooth areas from rough areas. The radius could be changed to find more or less detail associated to the smooth/rough factor. The problem is you will have to write your own code to make this filter work. Here is a poster that has an example in the upper right section of the poster: http://www.hitechmex.org/publications/imlf2011/index.html

Hope this helps or better I home someone has a better solution for you.

You can use CloudCompare software.

it is free and it has roughness calculation.

https://www.danielgm.net/cc/

Hi Amir,

the following papers provide some interesting info on the topic of roughness and how to compute it:

* Kushunapally, R., Razdan, A., Bridges, N., 2007. Roughness as a Shape Measure. Computer-Aided Design and Applications 4 (1-4), 295–310. DOI: 10.1080/16864360.2007.10738550 (download here: http://www.cad-journal.net/files/vol_4/Vol4Nos1-4.html)

* Nocerino, E., Stathopoulou, E.K., Rigon, S., Remondino, F., 2020. Surface Reconstruction Assessment in Photogrammetric Applications. Sensors 20 (20). Doi: 10.3390/s20205863 (Download here: https://www.mdpi.com/1424-8220/20/20/5863)

As these paper state, one first must define if a local or global roughness measure is needed. Recently, machine learning approaches have been leveraged to estimate roughness, but the more common approach is to use 3D-capable tools to compute and visualize roughness. Two good and free tools are:

* CloudCompare, which can directly compute local roughness (info here: http://www.cloudcompare.org/doc/wiki/index.php?title=Roughness, download here: https://www.danielgm.net/cc/)

* Meshlab, like CloudCompare a tool that is capable of many mesh and point cloud operations (download here: https://www.meshlab.net/#download). Although there is no direct “roughness” measure in Meshlab, the software offers several ways to compute surface curvature, which can be used as a proxy for roughness. You will find some useful information here: https://stackoverflow.com/questions/59194552/meshlab-does-the-topology-of-my-mesh-effect-the-curvature-results

Hope that helps. Cheers!

Geert

Hi Amir,

For Roughness and other ISO 3D texture parameters, check pp. 109-116 and pp.189-196:

* Moitinho de Almeida, V. (2013). "Towards Functional Analysis of Archaeological Objects through Reverse Engineering Processes". Ph.D. Thesis. Barcelona: Universitat Autònoma de Barcelona (UAB). http://hdl.handle.net/10803/129161

Thesis Towards Functional Analysis of Archaeological Objects throug...

Hi Vera, are you talking about ISO 25178: Geometric Product Specifications (GPS) – Surface texture on 3D models? I've checked your thesis.

I do not know any free software that can do that. I use MontainsMap: https://www.digitalsurf.com/

Roughness relates to curvature and can be computed using Integral invariants: https://youtu.be/W9U6hT96l5E The video shows the volume integral invariant computation via the GUI. For roughness the surface integral invariant is more suitable as it relates to mean curvature. It can be computed using command line tool "gigamesh-featurevectors". The generated file (...surface.mat) can be imported to GigaMesh as well as to Matlab/Octave.

I have applied photogrammetry for the study of roughness on faults. You can keep your surfaces as dense point clouds, then you can study them with a wide range of software. I have used Matlab or CloudCompare for example. About how to characterize a rough surface then, this is another topic...

If you are interested have a look at the following publications:

https://doi.org/10.1016/j.tecto.2017.08.023

https://doi.org/10.1130/GSATG506A.1

https://doi.org/10.1130/B35661.1

Dear Amir hossein Momeni

I will prefer to recommend you try a open-source software CloudCompare：

http://www.cloudcompare.org/doc/wiki/index.php?title=Roughness

http://cloudcompare.org/forum/viewtopic.php?t=3823

Or, perhaps some open-source code on github, e.g.:

https://spamlab.github.io/pub/ISRM2019/ISRM2019_Poster_SfM_Surface.pdf

https://www.researchgate.net/publication/312019448_3D_point_cloud_analysis_for_surface_roughness_measurement_Application_of_UAV_photogrammetry

Kind Regards,

Zhouxuan Xiao