Saturday, September 24, 2022

Kipontie, what a wonderful Finnish cave!

 

Why look for limestone caves and stalactites, when in Finland you can find moss-stalactites? And besides stalactites, the Kipontien luola (cave of the scoop road) is an exceptionally nice experience. Most Finnish caves are cracks on a cliff or space under boulders. But Kipontie is a hole in the ground, on a more or less level surface, even if inside you can see that it is made up of cracks and boulders. But it is dark, it is tight, actually make that very tight, and downright claustrophobia inducing hell hole. Just like caves should be!

Oddly enough, there hasn't been that much stories about this cave, I have not been there even if it is close to my summer cottage, nothing in Retkipaikka that I can find, and I have not heard about it in the Finnish Caving Association's discussions. In my mind this cave is such a challenging caving experience, dark, and long enough to warrant being compared to Turku's Luolavuoren luola (cave of the cave hill :-) ) or Finland's major karst cave, Torholan luola (cave of Torhola) in Lohja.

But yay, a few years ago Seikkailun lumous made a map of this cave [1]. Very nice! That map is further down in this article, but I used my 3D phone scanner to construct a new map. It is not easy to get a high-quality scan in very tight places, but I managed to get enough to run the model through my map generator, and got this:

Based on the model, I also calculated that the cave is about 35 meters long, all parts considered. There's also cross sections in my map, such as this one about the Kuoppa (hole) in where the left passage of the cave goes down through a tight spot:


To make the model, we did crawl as far as one can to the cave, although I did not go to the Salainen alahuone (secret lower room) on the left side passage, the entrance to the room was too scary and tight. But my son did, so the 3D model is relatively complete.

The full map in PDF is here. The 3D model can be downloaded here or rotated on your screen here.

The cave is in Orivesi, and about 45 minutes drive from Tampere. The coordinates are N 61.685539 E 24.257283.

Here's by the way the Seikkailun lumous map, made by hand from measurements. I can't fully explain the difference to my map. I should note that the 3D scanner and softwares are quite experimental, and often seem to make mistakes or produce shadow results. But I also think that we covered bigger part of the cave. It is possible that some of the side passages either in the below map or our map are also errors. And since I have to for now construct the 3D model in parts, I can easily introduce alignment errors where the cave parts are not in the right angle against each other.

More pictures, first about the entrance:



 


An inside view, from the left passage and the Nouseva käytävä (rising passage):


The author, apparently looking for gold?


This is how kneepads should look like after caving:

References:

[1] Seikkailun lumous. Kipontien luola. Suomen luolaseura. Luolaseura.fi.

This article has also appeared in TGR. Read more urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net. Read the full Planetskier series at planetskier.net, or all blog articles from Blogspot or TGR. The Cave Outliner software is open source and available on GitHub. Photos, videos, models, maps, and text (c) 2022 by Jari and Janne Arkko. The Seikkailun lumous map is obviously from Seikkailun lumous and Suomen luolaseura. All rights reserved.

Sunday, September 11, 2022

Schraubenfallhöhle

 

Schraubenfallhöhle is a cave, an underground river. It starts from one raging waterfall of the Tuxbach dropping into a wide hole in the ground, and emerges a bit later to start another waterfall. It is located by the end of the Hintertux valley, right by the lowest lift station taking people up to the Hintertux glacier.

You can read more about this cave (in German) from this research article, "Die Klamm des Tuxbaches bei Hintertux (Tirol) und das Alter der Schraubenfallhöhle", appeared in Die Höhle in 1967, issue 018. The article is by Hubert Trimmel.

Entering the cave is impossible, as it is maybe fifty meters down in a deep gorge. I'm not sure if the cave is otherwise visitable, perhaps during dry seasons and when not much meltwater is coming down from the mountains. The article referred to above seems to describe what's inside the cave, so people have been there.

I was therefore not in the main cave, but visited a couple of tiny caves on the side, though Austrians would probably not call these caves at all. Just a few meters long, enough space for one person. The first side cave map is here, a rotatable 3D model here, and the model can be downloaded here. The second side cave map is here, a rotatable 3D model here, and the model can be downloaded here.

Video:

Views from the top waterfall falling into the cave:




Marble at the bottom waterfall:

Side cave 1:

Side cave 2:

Read more urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net. Read the full Planetskier series at planetskier.net, or all blog articles from Blogspot or TGR. The Cave Outliner software is open source and available on GitHub. Photos, videos, models, maps, and text (c) 2022 by Jari Arkko. All rights reserved.

Wednesday, September 7, 2022

Vantaa is too tight


We went for a short caving trip in Vantaa... visiting our old friend Kalkkikallion ketunluola. It is still a great small cave, dark and tight. But one of the other caves, Kalkkikallion matalan katon luola (the low roof cave) was even more interesting. I had been there before, and didn't want to go through between the two entrances. Now I tried again... and still didn't want to go through. The cave gets progressively lower between two rock layers, and just before exit it is less than 20 cm... maybe someone else wants to try?

The above picture is about me trying, but I did give up.

I did generate a 3D model and a new map of the main ketunluola, however. See the PDF and the model on your browser, or download the model here

There's also a third cave in the area, the Kalkkikallion nuotiopaikan luola (fire pit cave). But as we walked around, I realized that there was even a fourth cave, one with a very large flat boulder covering an area. Lets call it the Kalkkikallion kivikatoksen luola or rock roof cave. Here's a picture

The caves are in these locations:

Read more urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net. Read the full Planetskier series at planetskier.net, or all blog articles from Blogspot or TGR. The Cave Outliner software is open source and available on GitHub. Photos, videos, models, maps, and text (c) 2022 by Jari Arkko and Janne Arkko. All rights reserved.

Saturday, August 20, 2022

Schneefleckhöhle

 

Continuing my quest for using lidar in newest phones to build 3D models of caves. Here we have a scan of the Schneefleckhöhle, a 160-meter marble cave in the Zillertal mountains in Austria. The cave has been scanned with iPhone 12 Pro and Polycam, using lights and the phone mounted on a Benro selfie stick. Scanned segments were put together in Blender and used for fly-through animation. I can also feed the 3D model to my "Cave Outliner" software that draws a plan view map and cross sections based on the model. Lots to improve in various pieces of software, and scanning an entire complex form is very hard. While all of this is very experimental, bleeding edge technology it is also very exciting, and already offers some stunning views onto a caves.

Here's a video:

And the some parts of the cave map in pictures below. However, due to the limitations of the blogger platform, it is much better to view them by clicking on the plan view, vertical cross section, and cross section C pictures instead.












The full map is available in PDF here. Note that the map pictures above have been slightly modified manually, to flip them to a more suitable presentation orientation, and to add an entrance (which Cave Outliner can not yet reliably do by itself).

The cave model can be downloaded here in GLB format and here in Blender format. A rotatable model on your browser screen can be started here.

The Benro "3D scanning stick" looks like what is shown below. Attached are X-Grip attachments to hold the phone and the Lumonite lights:

In the following I go through what the process is for making these kinds of scans:

  • Have a phone, needs to be an iPhone pro model 12 or later. You'll also need to have enough free memory and a scanning app such as Polycam installed. You'll need the commercial version of the app, as data export will require that.
  • Setup a lightning method. This can be just your helmet or hand-held light, but it is better to use a setup where the phone sensor and the lights are built to point to the same direction for more even lightning.
  • Start a new scan, set a lidar and camera mode to get both the shape and the texture. Carefully and with modest movements start scanning the cave entrance and the tunnel forward. You will need to cover different holes and side rooms, under bigger boulders, etc as well.
  • To ensure that software can process your scan results, stopping the scan, storing the results, and starting a new separate model is advisable every now and then. In my experiments doing this every 20-50 meters in a normal cave tunnel (with some forms and other complexity) is about right.
  • After each scan, or at the end when your phone is reconned to power, process the scans in the app. I have used the custom setting with maximum range and highest accuracy.
  • Upload each scan to iCloud by exporting each model in, say, the GLTF/GLB format.
  • Import one model at a time to a post processing software such as Blender. Cut away erroneous or shadow parts, if any.
  • Merge the models by first removing any excess overlap in Blender object editing mode and then aligning the different parts according using tock features (ledges, boulders, depressions, etc.) as a guide to get best alignment.
  • Store the resulting merged model, in Blender as a Blender file, for instance.
Optionally, if a map is desired: 
  • Convert another copy of the model to STL format, e.g., in Blender.
  • Feed the Cave Outliner and use the --auto option to get the best default settings. If you want to, you can provide additional information such as name of the cave, location and coordinates in extra options. Cave Outliner produces an SVG file that contains a map of the cave. 
  • Use Apple Graphic or other software to convert the SVG file to PDF, and share the map.

Finally, also optionally, if a fly-through video is desired:

  • Setup a camera, a light, and attach them together in Blender. The light will provide light as the camera travels through the model in the animation we are about to set up.
  • Use the Shift-F to enter the fly through mode (you may need to configure Blender to recognize the Shift-F).
  • In Fly Through mode, use 'w' to go forward, 's' to go backward, and 'a' or 'd' to pan sideways.  Press 'i' to insert a fixed frame for your animation. You will only need a few fixed frames, Blender will interpolate your position for moving between the fixed frames.
  • Click on Render Animation to produce an animation image sequence.
  • Use, for instance, Quicktime to import the image sequence and convert it to a video file.

But there are also issues, as this is early use of this technology:

  • The first issue is that you have to be very careful and methodological about the scan. If possible I like to rotate the phone on a stick and progress through a tunnel, but often that's not possible. In the video you can see some of the holes that started to creep into the model when I was running out of time and doing things too quickly. Of course tons of boulders and cave forms don’t make the careful coverage easy or even possible in all cases.
  • The scan recording softwares on the phone - while they have improved - are still not really designed for this and have many problems. One big issue is that they are unreliable and can’t handle too much data so scans need to be done in pieces, nine pieces in this one for instance.
  • And given the above, you will have many parts, how do you then put them together and align properly? In theory one could imagine some auto-alignment but we don’t have that. I put them together manually (based on shapes etc) but that introduces a source of error of course. One could imagine also some hybrid scan + disto reference points process.
  • Accuracy. The accuracy seems to vary and I often get shadow walls and the like if something is scanned twice for instance. The manual handling of the scan carefully affects this of course, but also softwares and sensor physical capabilities contribute.
  • Range, the five meter approximate range of the sensor may even be slightly exaggerated, and it definitely makes things hard in bigger cave halls. Based on advice from my Icelandic friends though, the selfie stick method helps here. Still, person's height plus selfie stick length plus sensor range is somewhere under 10 meters, so rooms higher than this cannot be easily scanned in their entirety.
  • Finally, interpreting a simplified cave map from a 3D model is actually harder than one thinks in the beginning. For instance, I’ve spent a ton of time thinking about what the definition and math for an ‘entrance’ is. And have had fun finding algorithms to filter out small scanning irregularities like a small missing parts behind a rock or a cavity etc. This presentation from November 2021 outlines some of the difficulties with the definitions.
Previous articles about the use of 3D modeling and iPhones in caves can be found here: scanning Austrian caves (TGR),  scanning the Grafenloch cave (TGR), scanning the Lummelunda cave (TGR), Torhola cave in 3D (TGR), automatically generated maps (TGR), first article in Swedish caving magazinenewspaper uses my 3D models, first cross sections (TGR), and Kauniainen 3D models, Högberget in 3D (TGR). There's also been articles in the Swedish Caving Association's magazine Grottan (2021), the Finnish Caving Association's magazine Luola (2021), and the British CREG Journal (issue 115, 2021).

This article has also been published at TGR. Read more urban exploration stories from theurbanexplorer.net, and other underground stories from planetcaver.net. Read the full Planetskier series at planetskier.net, or all blog articles from Blogspot or TGR. The Cave Outliner software is open source and available on GitHub. Photos, videos, models, maps, and text (c) 2022 by Jari Arkko. All rights reserved.

Sunday, August 7, 2022

More of the same: pool in a plain hotel in no particular place

 

Hampton Inn... a good but not remarkable hotel... New Jersey... nice state but not remarkable... South Plainfield... newer heard, but ok and again not remarkable. A plain hotel in Plainfield?

What's to do? Swim in the hotel pool!

A swim is a swim is a swim. Nice to dip in the water on a hot day. Not bad!

I was at Hampton Inn South Plainfield-Piscataway, South Plainfield, New Jersey (link here).

For more sauna and swimming stories, check out planetswimmer.com and saunablogger.cool websites! And of course the Planetcaver, and Planetskier blogs for other stories in Blogspot and TGR! The photos and text (c) 2022 by Jari Arkko. All rights reserved. I never take photos of other saunagoers or swimmers and visit when there is simply no one else or the facility has been closed or booked only for me.

Finnair A350 on short haul routes

Interesting... ended up on the Finnair A350 on my way back home from London. The A350 is such a nice airplane.

I was also thoroughly enjoying the live camera features on this aircraft.


For more flying stories, check out the planetflier.com website! And of course the Planetcaver, and Planetskier blogs for other stories in Blogspot and TGR! The photos and text (c) 2022 by Jari Arkko. All rights reserved.

Lounges .. now we are talking...


... or barking? 

What a wonderful refreshment spot for the animals passing through the airport! Well done, Philadelphia International! Never seen a lounge so much better suited for the furry passenger's needs!

For more flying stories, check out the planetflier.com website! And of course the Planetcaver, and Planetskier blogs for other stories in Blogspot and TGR! The photos and text (c) 2022 by Jari Arkko. All rights reserved.