Unroll other shapes

[Kate3388]

I work as an archaeologist and regularly dig holes 1m x 1m. I take a series of images of the walls of the hole and create a point cloud .obj. I then cut the obj into 4 parts representing the walls of the hole and manually create an unrolled version of the walls. Is it possible to use the Unroll tool on a square. Cutting the point cloud and putting back together the wall is labor intensive I'm hoping for a better way.

[daniel]

You could use the 'Unfold' feature of the 'Section extraction' tool:
https://www.cloudcompare.org/doc/wiki/i ... a_polyline

This will do exactly what you want... but on a point cloud! So if it's acceptable to you, you can sample a lot of points on your OBJ mesh first, and then 'unfold' the resulting cloud.

[Kate3388]

I can export the 3D model I created of the excavation as a laz file. Then I can create a polyline and unfold the cloud. How can I export the result. I wish to annotate the unfolded excavation walls using another piece of software and include it as an image in a .pdf

Thanks

Kate

[daniel]

Well, I guess it depends on the format the other tool is supporting? CC can export clouds and meshes in various open formats. And if it's "2D", you can also create a 'raster' (grid) and export is as a raster file or a simple image.

[Kate3388]

Hello

Thank you for the prior responses. I'm having difficulty with the sides of the unit overlapping at the bottom of the units. I'm creating one polyline at the top of the unit and unfolding it a distance of 1m. I've attached an image of the result. Any suggestions would be appreciated.

[Kate3388]

I believe that the overlap is a reflection of the fact that the surface of the excavation not level. I created the polyline by tracing the surface. Is there a way to generate a polyline that would sit above the excavation units or maybe at the centre of the unit walls and be a consistent Z.

[daniel]

What does the original cloud look like? And what does your polyline look like? I'm a bit lost here...

[Kate3388]

Hi, I've attached a few images. Thanks for looking at this and if you need anything else, please let me know.

[daniel]

Ah, I better understand. Are the walls vertical? Can you change the orientation of the cloud (with the 'Edit > Translate / Rotate' tool for instance) so that they are really almost invisible?

[Kate3388]

Yes I can and that is the position that I had the point cloud in when I created the polyline. I've attached an image. The tool is now also grey out and not available I have selected it in the DB tree. The target in the image is on the bottom of the excavation. There are also several targets on the sides of the excavation pit so that I can in a additional step georeferenced the images.