Talk:3D printing of digital elevation models with QGIS

DEMto3D "spacing" setting -- Monolith (talk) 12:43, 17 January 2019 (CET)

Hi Daniel

Thanks for the helpful tutorial on using this plugin. I've been struggling with the "spacing" setting, though, as referenced in section 3.1 on this page -- what exactly does it control? I'm also confused by the instructions next to the setting, e.g. "minimum recommended 0.2mm"... in which direction do we move this setting to get away from the minimum? As model size increases, the minimum recommended spacing value gets larger, so I've been assuming that this setting is counter-intuitive with its use of language like "minimum" and "larger", in that for a model that has 0.2mm recommended as a 'minimum', the only direction you'd want to go is to a lower value, e.g. 0.1mm.

I tried to get in touch with the author of the plugin without any success, so hoping you might have some insight. Thank you for making this wonderful resource available!

Monolith (talk) 12:43, 17 January 2019 (CET)

Re: DEMto3D "spacing" setting -- Daniel K. Schneider (talk) 17:38, 17 January 2019 (CET)

Hi I am not really sure and I didn't print any model since I wrote this article.... i.e. I probably forgot some stuff I intuitively understood. If I understand right, the 0.2 mm refers to the distance of the points in the generated STL file, so it's not dependent on the size of the model.

My math skills are very low, but roughly: just the number dots of a 20cm x 20cm model with 100 layers is 1000 x 1000 x 100 = 100M. That may fit huge file sizes. E.g. I got 750MB for Grand Canaria as described in 3D_printing_of_digital_elevation_models#Meshlab.2F_Meshmixer_example

So if you go down to 0.1mm you will get files > 1GB (sorry, I don't have time for testing myself and I probably should install a new version first).

- Daniel

- cheers ! Daniel