Thanks for all the info Kevin. I think I follow and understand your workflow.
I have been using CloudCompare and MeshLab, however the best results have come from very expensive LiDAR instrument manufactures software and other 3rd party paid for software. Bit out of my budget I'm afraid. To a great extent this may be me not knowing how to use the open source software correctly so as ever it's work in progress. Surface scan using a drone next, can't wait! Has anybody got an answer to the Therion KML model output question, what information does Therion need to create this? It seems to me that just having cave walls drawn is not enough even though I can get good pdf output. Nick -----Original Message----- From: Therion [mailto:[email protected]] On Behalf Of kevin dixon Sent: 20 June 2019 11:44 To: List for Therion users <[email protected]> Subject: Re: [Therion] Using 3d Scan Data To Create A Map Those with their own LiDAR instrument will usually have access to their LiDAR manufacturer Software and this often includes automated rendering of man-made surfaces - results quality depend a lot on the LiDAR resolution and accuracy. Natural surfaces such as caves are more difficult for Point Cloud software to deal with automatically. For the rest of us, you may wish to consider the following open source software for Point Clouds: MeshLab - lots of functionality, poor interface, I used this a decade ago when there were few open source options CloudCompare - nice interface, I have not used it for a while ParaView - uses PCL (Point Cloud Library), PCL can be used direct depending on your coding ability PDAL - a library of point cloud tools, need to use something like QGIS for results visualisation Blender - more for 3D videographics 3DTK - 3D Toolkit, not familiar with Other options are available. Kevin Dixon On Thu, Jun 20, 2019 at 9:36 AM Martin Sluka via Therion <[email protected]> wrote: > > Isn’t it as call for nuclear aircraft carrier to kill a fly? > > Martin > > Odesláno z iPhonu > > 20. 6. 2019 v 9:33, Pavel Herich <[email protected]>: > > > This software should do it: > > https://geoslam.com/hub/ > > P. > > > > > > Dňa 2019-06-20 09:26 Martin Sluka via Therion napísal(a): > >> I’m curios if there is a software able to create vector map > >> outline from cloud data automatically. > >> Martin > >> Odesláno z iPhonu > >> 19. 6. 2019 v 23:13, kevin dixon <[email protected]>: > >>> Nick, > >>> I have both DistoX2 and LiDAR data for parts of the same cave. > >>> All the LiDAR scans were registered to create a single model as > >>> normal for LiDAR. > >>> The individual scans were then decimated in the Point Cloud > >>> Software using a suitable distance to nearest neighbour. I found > >>> Survex gets a bit overwhelmed with millions of LiDAR data so you > >>> may have to experiment with a suitable distance between adjacent > >>> LiDAR data. Each decimated individual scan was then output to > >>> LibreOffice Calc and new ranges, bearings and inclinations > >>> calculated to create single station Survex files with lots of splays, now > >>> all orientated the same way. > >>> Dummy traverse observations were created within Survex to link all > >>> the LiDAR scan stations based upon the Point Cloud registration > >>> coordinates and elevations of the scan stations. > >>> I then manually matched the Survex output of the above LiDAR data > >>> to some known DistoX2 observations or in your case, perhaps known > >>> show cave outline. You can do this within Survex by having your > >>> non-LiDAR data as another survey then using a Calibrate Compass > >>> figure (may require up to +/-180degrees) within the LiDAR Survex > >>> data to change the orientation so as to match the known and also > >>> setting one of the LiDAR stations within the Dummy traverse > >>> observations to coordinates and elevation that give a good fit > >>> with the known data. Several iterations are needed with these. > >>> Hope that is self explanatory. > >>> Has worked for me - I have a DistoX2 Survex model with very > >>> detailed LiDAR data in two large chambers - the resulting LOG file > >>> looks a bit weird eg. > >>> 1 8659-node. > >>> 1 19071-node. > >>> 1 21844-node. > >>> 1 22774-node. > >>> 1 23053-node. > >>> 1 24470-node. > >>> 1 25278-node. > >>> As a side note, part of my project includes a Show Cave and I have > >>> not had a problem with insitu metalwork there or on scaffolded > >>> sections of the cave. I have always kept the DistoX2 well away > >>> from metalwork and when the passage is narrow with metalwork, I > >>> have used an intermediate station with DistoX2 observations to it only, > >>> never from it. > >>> I have considered the use of turned angles to get through a > >>> serious metaliferous section - the Leica DST360 could do this for > >>> you or a small theodolite - use magnetic obs at each end to orientate it > >>> all. > >>> Kevin Dixon > >>>> On Wed, Jun 19, 2019 at 9:02 PM Nick Bairstow <[email protected]> wrote: > >>>> Hi, Something a bit different for the clever people out there. > >>>> I have been playing with some 3d scan data and have attempted to use it > >>>> to create a Therion map. > >>>> Firstly we put created an outline of the cave passage using point cloud > >>>> software and exported as dxf. > >>>> I turned the dxf into a background sketch and drew around it and could > >>>> output a nice pdf of our cave. Also did a manual scaling. So far so good. > >>>> I added a dummy station and gave it entrance coordinates, then exported > >>>> as a KML model. When I open the output file Google Earth fly’s to the > >>>> correct spot and shows a pin with the cave name but no cave. > >>>> My question is , does this fail because we have no survey data, > >>>> centreline etc and it is impossible to do this or am I missing something. > >>>> As an alternative I can export to an esri shp file and run that > >>>> though Qgis and get what I want but as I am going to attempt to combine > >>>> the 3 scan data with a several normal disto surveys I would like to see > >>>> Therion Kml output work if possible to save lots of messing around. (GIS > >>>> makes my head hurt) On a side note using the point cloud software I can > >>>> slice though the scan data on different planes and pick up lots of > >>>> detail, rocks and boulders etc. Using the dxf/background image method I > >>>> should be able to get a very accurate representation of the passage. I > >>>> can hear you all saying what the hell is he doing that for when he could > >>>> just survey the cave in the normal way! Well the cave is a show cave and > >>>> absolutely rammed with metal walkways and cables. Disto tests showed > >>>> wild inaccuracy’s so it was looking like the only viable option was > >>>> going to be to use a Total Station device which we don’t have. We then > >>>> had a very kind offer to scan the cave, this has proved to be very > >>>> interesting but drawing a normal map is a bit of a challenge although it > >>>> seems not impossible. > >>>> Any help would be appreciated. > >>>> Nick > >>>> _______________________________________________ > >>>> Therion mailing list > >>>> [email protected] > >>>> https://mailman.speleo.sk/listinfo/therion > >>> _______________________________________________ > >>> Therion mailing list > >>> [email protected] > >>> https://mailman.speleo.sk/listinfo/therion > >> _______________________________________________ > >> Therion mailing list > >> [email protected] > >> https://mailman.speleo.sk/listinfo/therion > > _______________________________________________ > > Therion mailing list > > [email protected] > > https://mailman.speleo.sk/listinfo/therion > > _______________________________________________ > Therion mailing list > [email protected] > https://mailman.speleo.sk/listinfo/therion _______________________________________________ Therion mailing list [email protected] https://mailman.speleo.sk/listinfo/therion _______________________________________________ Therion mailing list [email protected] https://mailman.speleo.sk/listinfo/therion
