DistoX2 an alternative

maxf

New member
Dave254 said:
Do you have any data examples you can share that you have collected with it ?

To reduce the amount of points you can use the subsample tool and select a more appropriate point spacing.

Cloud compare also can reduce the amount of figures in a coordinate (if you points are georeferenced to a datum, if not then this won't save much unless it's a very large area), for example if all of your points fall with say a 1000m X 1000m box and are referenced to to OSGB36 it could remove the first common digits from the Eastings and northings, if often prompts this when you load in a dataset but you can write out a shortened file if this is desirable.

Unfortunately not yet, I have literally taken it out for a 2 hour test run the evening before lock down started and so I have only produced the quick test which I have put on this thread.

The actual data output consists of 2 files, a survey file and a point cloud file. The survey file which is in a format for walls (its American!) contains the normal survey data (survey stations, distances, azimuth, inclination etc) this file layout could be altered for a European survey program if required. The second is just the point cloud data file. The survey file allows you to check the survey file and adjust any loop closures prior to adding the point cloud. The point cloud is then put into a point cloud program (I have used cloud compare because it is free!) this will then produce the 3D map. I haven?t yet found the best method for sharing these point clouds due to the file size (the example I have attached above is only a small section of passage and consists of 1.6million data points)
 

Dave254

New member
Subpopulus Hibernia said:
Neat. Do you have a particular need to do a 3D scan or are you looking to use it for general surveying?

I have not got a particular scanning project in mind. I had seen and was impressed the Zebedee lidar (apart from the cost!) and I then stumbled across the Caveatron project and thought it would make an interesting winter project.
 

pwhole

Well-known member
Bob Mehew said:
The other thing to bear in mind is that whilst most free 3D scan presentations just show the external 'skin', I have no doubts that software is coming along which will enable you to get inside that skin to give you a visual impression of the cave.

Most standard 3D packages (like 3DS MAX, Maya etc.) will allow 'double-sided' polygons to exist - in that they are rendered on the inside, outside or both. It's usually clipped in the settings to only render the 'outside' of a model, as that's generally the only part the viewer will see, and it's a waste of computation to render something you never see. But if you set the camera and lighting to be inside the model, and flip the polygon rendering to the inside, then it would be easy to 'fly through' the model. Assuming also that the point cloud model can be converted to a 'standard' 3D object format. Obviously resolution would be an issue, as the polygons would have to be really tiny (so a massive model) to look good. But maybe point-renderers can handle this better and make it scalable - I've been out of the loop of this industry for some time, so I'm not sure how far it's developed in this direction.
 

Bob Mehew

Active member
pwhole said:
Most standard 3D packages (like 3DS MAX, Maya etc.) will allow 'double-sided' polygons to exist
Could you see if any free 3D rendering software offers similar capability to the commercial packages you mentioned?

I have got someone looking at manufacturing the main PCB so may well have a few spare.  (It being as cheap to print a number as just one.)  If any one is interested in making the project, please PM me.
 

pwhole

Well-known member
I have Blender but I find it rather difficult to get my head around. However, I just had a chat with my Blender expert friend who says that it's perfectly possible to do fly-throughs inside the model, and it doesn't even have to be 'rendered' as an animation, but can just be interacted with in real-time. I'll load up a model now and just see what it looks like inside ;)
 

NigelF

New member
re #23  I am interested in a PCB for a Cavetron. 
My only slight hesitation is that the 2D scanner is only rated to 12m with a white target by the manufacturer. However, it may be that the laser is operated at a bit more power by the Teensy compared to the board that the scanner is supplied with.
 

Dave254

New member
The RPlidar A1 does have a 12m radius (so it will scan the sides of a 25m diameter passage if your going down the middle!) The 12m limit is a limit of the lidar itself so you wouldnt be able to increase that.  However you can do multiple lidar traverses and overlay them (one down each side of a passage for example), but this wont help you out if you have a passage this is more than 12m high.

There are other lidars that have a wide scanning range (Such as the Rplidar A3), however at around ?500 it is considerably more expensive than the ?65 A1 version.
 

Tommy

New member
Potential other software options:

Meshlab
Paraview

Haven't assessed the suitability, just throwing them in.
 

NigelF

New member
re #28 RPLIDAR.

It seems there is also an A2M6 with 18m scan radius, currently just over $300.
I wonder if the 12, 18 or 25m ranges are real in the low reflectivity setting of most caves; particularly since the Slamtec info mentions white walls.
 

Tommy

New member
pwhole said:
Ooooh - MeshLab looks VERY interesting ;)

I think both meshlab and paraview were part of my workflow for turning survex data into an STL for 3d printing. There's a thread on here somewhere. I didn't use any of the functionality other than import and export, hammer to crack the nut of file conversion.

Company ive worked at used meshlab for working with lidar point cloud, photo, and radiation scanner data. It's very powerful, and free!
 

Tseralo

Member
Bit late but I?ve got a printer that can do 200x200x200mm happy to run bits off for people the material cost is penny?s in relality.
 

FabianE

New member
I am just in the process of building one of these Caveatron units.
Ordered the PCBs which have now arrived.
Minimum order is five units so I have three PCBs spare which people can have for their own setup.

I'd ask for like ?2.50 a board? That covers the manufacturing costs and postage + import charges.
 
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