HDMapping, scanned a mine tunnel, tunnels aren't "syncing" up

[DooDip]

I'm out in the field unfortunately. I downloaded the YT videos to watch offline. I scanned a short mine in a loop. Walking into the tunnel and going down into the mine, walked around, and came back out. Unfortunately the same tunnel coming back out is below the way I entered. Same tunnel, 2 different elevations.

Where in the software do I sync the same tunnel together? Which options do I use? I thought I was following the correct tutorial, but I'm missing something.

Also, my mid-360 is mounted at roughly 45 degrees so it scans the floor and the ceiling (and not my head and body.)

Trying to figure out the correct workflow out here in the desert. Thanks!

[JanuszBedkowski]

Hi, good point, hopefully this diagram helps

[yuckinus]

@DooDip don't know if you're in the WhatsApp group so reposting my message from there which think also aplies here:
"you have to understand constrains, first ignoring the rtk and disto stuff, just basics. Lidar unit is the eye(s) and internal ear so you have sight and balance to simplify understanding. After session recording starts, at all times the lidar must see as much as possible as to know where it is between movements and time. Any loss of "vision" (field of view) like a passage too narrow (considering minimum lidar distances), obstructions in field of view or things moving in field of view (many people in tight space) will crash odometry. At all times movement must be consistent, any rapid change of direction/speed (sudden twist of neck if wearing on helmet or bumping the helmet against ceiling will create a jump in IMU that will crash odometry. Besides these two constrains, you must take into account that odometry is not 100% perfect process so you always have small drifts or errors that need to be addressed. That's why consistent workflow is needed so you can get consistent results: to use control points workflow you need the back and forth scanning Tomi was talking about, always start start/pause/stop with lidar level, always make these pauses in some "waypoints", where waypoint is: start same as stop (location, position), intersections with other galleries (before entering them after returning from them) and easily recognizable locations along a route from place to place (no further apart than a few tens of meters). This enables you to use CP and very quickly identify and fix most common issues before even talking about rtk and distox"

On the other hand, using 1 lidar arrangement in cave environment (tight spaces) is not ideal and comes with challenges. Mounting it on the helmet poses other challenges again.

[Migi89]

can you send a message to the whatsup group?
Thanx.

[JanuszBedkowski]

Please send me You phone number to my email januszbedkowski@gmail.com so I can add You to WhatsApp group

[DooDip]

Awesome, thanks all. I'm using a handheld mount in a very large (short) mine. A quick in and out.

Is there something I should be doing with the mid-360 and Mandeye? Do I need to add reflective tape in a random array on the floor/wall/ceiling so the lidar/software can detect "oh we're back at X" ?

Normally I set it on the ground, turn it on, start scanning and let it sit there for a minute or 2. Then I'll slowly pick it up and walk forward into the tunnel and probably every 50ft, slowly spin around in a circle, I've tried walking back to the entrance, I've tried continuing on, at some point my tunnel starts climbing up like a roller coaster.

I can look at manual loop closure (?) and find identical spots, but trying to "sync" them together, I must be doing something wrong. I add the edges, run optimize, they don't "sync". Maybe they are too far apart?

If there's a manual I can read, guides, tutorials, etc, please let me know. I feel like I'm pulling different info from different places.

I don't have WhatsApp but I can get it if that would help. Thanks again

[JanuszBedkowski]

Can You share data? So i can investigate the issue ?Wysłane z iPhone'aWiadomość napisana przez DipDoo ***@***.***> w dniu 21 kwi 2026, o godz. 20:54:DooDip left a comment (MapsHD/HDMapping#423) Awesome, thanks all. I'm using a handheld mount in a very large (short) mine. A quick in and out. Is there something I should be doing with the mid-360 and Mandeye? Do I need to add reflective tape in a random array on the floor/wall/ceiling so the lidar/software can detect "oh we're back at X" ? Normally I set it on the ground, turn it on, start scanning and let it sit there for a minute or 2. Then I'll slowly pick it up and walk forward into the tunnel and probably every 50ft, slowly spin around in a circle, I've tried walking back to the entrance, I've tried continuing on, at some point my tunnel starts climbing up like a roller coaster. I can look at manual loop closure (?) and find identical spots, but trying to "sync" them together, I must be doing something wrong. I add the edges, run optimize, they don't "sync". Maybe they are too far apart? If there's a manual I can read, guides, tutorials, etc, please let me know. I feel like I'm pulling different info from different places. I don't have WhatsApp but I can get it if that would help. Thanks again —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[JanuszBedkowski]

Can You share data? So i can investigate the issue ?Wysłane z iPhone'aWiadomość napisana przez DipDoo ***@***.***> w dniu 21 kwi 2026, o godz. 20:54:DooDip left a comment (MapsHD/HDMapping#423) Awesome, thanks all. I'm using a handheld mount in a very large (short) mine. A quick in and out. Is there something I should be doing with the mid-360 and Mandeye? Do I need to add reflective tape in a random array on the floor/wall/ceiling so the lidar/software can detect "oh we're back at X" ? Normally I set it on the ground, turn it on, start scanning and let it sit there for a minute or 2. Then I'll slowly pick it up and walk forward into the tunnel and probably every 50ft, slowly spin around in a circle, I've tried walking back to the entrance, I've tried continuing on, at some point my tunnel starts climbing up like a roller coaster. I can look at manual loop closure (?) and find identical spots, but trying to "sync" them together, I must be doing something wrong. I add the edges, run optimize, they don't "sync". Maybe they are too far apart? If there's a manual I can read, guides, tutorials, etc, please let me know. I feel like I'm pulling different info from different places. I don't have WhatsApp but I can get it if that would help. Thanks again —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[DooDip]

Sure, I will upload it to a Google share when I get better service if that works?

[JanuszBedkowski]

YesWysłane z iPhone'aWiadomość napisana przez DipDoo ***@***.***> w dniu 21 kwi 2026, o godz. 23:32:DooDip left a comment (MapsHD/HDMapping#423) Sure, I will upload it to a Google share when I get better service if that works? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>

[JanuszBedkowski]

Hi, no data provided, can I close this issue?

[DooDip]

Yes, sorry, I'm out in the middle of the desert. I'll upload the data when I can, thanks again.