I really need help
I sonar one lake in lowrance and i made a map of it with a reefmaster.
This is where knowledge ends...

If i export *.ASC to RM and inport it QGis i get 2D map but i can`t
convert it 3D map. Or if i inport *.ASC to MeshlAb its not look like
a map.

My problem is that i have to get convert RM 3D map to *.STL format
As easily as possible... so i would need hand to hand instructions.
To which format i export RM map so i get it easy open to QGis?
and how i convert it to QGis to 3D map, and what format i export it
Qgis so i get it easy open to MeshLab so i can export it again *.STL

Or if anybody know some easy way and better software for that
I am grateful for all the help.

You need a Tambourine without it, open source creativity doesn't work!

I but this link here to, maybe its help somebody :)
gis.stackexchange.com/questions/228827/g...ster-aster-gdem-data