3D printing for kids: modelling objects with Minetest

[spin]

makerware
has internal and surface errors, otherwise OK, so all the printers that work on x3g files can swallow those models no problem:

[spin]

Since materials aren't interesting, here's the above mod I posted, modified to export a 3D (on/off) bitmap instead of "color" data:

Prestidigitator, is there a possibility that you could push it to git?

Also, I'm afraid my programming skills are null :( I can do things from tutorials at this point, so I'm no use in doing anything with this for now. If someone who knows bpy could use that data to generate an object in Blender, that would be awesome, but it's way out of my league at this point I'm afraid (both skill- and time-wise).

[aldobr]

I found a much simpler solution, using FreeCAD.

Minetest side script :

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

-- FreeCAD exporting MOD - Minetest side
-- Copyright(C) 2014 - J. Aldo Gomes de Freitas Junior
-- GPLv2
-- Minetest side module

-- exporter proper
nodeexporter = {

   -- Populate this array with a list of nodes that should be rendered
   blockmapping = {
         ['default:dirt'] = 1,
         ['default:dirt_with_grass'] = 1
      },

   -- Exports a chunk of land starting at ax1, ay1, az1 and ending at ax2, ay2, az2
   exportblocks = function(athis, afilename, ax1, ay1, az1, ax2, ay2, az2)
      local destination = io.open(minetest.get_worldpath() .. "/" .. afilename, "w")
      local x, y, z
      local swapvar
      -- Verify and swap inverted coordinates
      if ax1 > ax2 then
         swapvar = ax2
         ax2 = ax1
         ax1 = swapvar
      end
      if ay1 > ay2 then
         swapvar = ay2
         ay2 = ay1
         ay1 = swapvar
      end
      if az1 > az2 then
         swapvar = az2
         az2 = az1
         az1 = swapvar
      end
      -- Write map chunk size
      destination:write((ax2 - ax1) .. '\n' .. (ay2 - ay1) .. '\n' .. (az2 - az1) .. '\n')
      -- Write map data
      for ly = ay1, ay2 do
         for lx = ax1, ax2 do
            for lz = az1, az2 do
               local node = minetest.env:get_node({ x = lx, y = ly, z = lz })
               local value = athis.blockmapping[node.name]
               if value ~= nil then
                  destination:write(value .. '\n')
               else
                  destination:write('0\n')
               end
            end
         end
      end
      destination:close()
   end
}

-- Register chat command
minetest.register_chatcommand(
   "mapexport",
   {
      params = "filename x1 y1 z1 x2 y2 z2",
      description = "Exports a piece of game map in a format that can be read by FreeCAD minetest importer plugin.",
      privs = { },
      func =
         function(name, param)
                  paramlist = string.split(param, " ")
                  local filename = paramlist[1]
                  local x1 = tonumber(paramlist[2])
                  local y1 = tonumber(paramlist[3])
                  local z1 = tonumber(paramlist[4])
                  local x2 = tonumber(paramlist[5])
                  local y2 = tonumber(paramlist[6])
                  local z2 = tonumber(paramlist[7])
                  nodeexporter:exportblocks(filename, x1, y1, z1, x2, y2, z2)
            return true, "Exported to " .. filename;
         end
   });


FreeCAD side script:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

# FreeCAD exporting MOD - Minetest side
# Copyright(C) 2014 - J. Aldo Gomes de Freitas Junior
# GPLv2
# FreeCAD side module

import Part, math

def makeCenter(x = 0, y = 0, z = 0):
   return FreeCAD.Vector(x, y, z)

def makeRotation(x = 0, y = 0, z = 0):
   return FreeCAD.Rotation(x, y, z)

def makePlacement(x, y, z, X, Y, Z):
   return FreeCAD.Placement(makeCenter(x, y, z), makeRotation(X, Y, Z))

def importvolumefile(filename, xscale = 10, yscale = 10, zscale = 10):
   cubes = []
   sourcefile = open(filename)
   xsize = int(float(sourcefile.readline()))
   ysize = int(float(sourcefile.readline()))
   zsize = int(float(sourcefile.readline()))
   for yposition in range(1, ysize):
      for xposition in range(1, xsize):
         for zposition in range(1, zsize):
            value = int(float(sourcefile.readline()))
            if value > 0:
               cube = Part.makeBox(zscale, xscale, yscale)
               cube.Placement = makePlacement(xposition * xscale, yposition * yscale, zposition * zscale, 0, 0, 0)
               cubes.append(cube)
   sourcefile.close()
   solid = Part.makeCompound(cubes)
   return solid

# replace filename - needs a beter interface
map = importvolumefile("c:/minetest/minetest-0.4.10/worlds/aldo/teste.vol")
Part.show(map)

Already works in my computer. I can - if trully needed - use FreeCAD boolean operations to fuse all cubes into a single entity, but this is quite a costly operation.

TODO:

Minetest side - Add parameter handling and checking. Populate the mapping table. There are only two entries right now. (dirt and dirt with grass)
FreeCAD side - Add file selection interface. Change tile color by minetest mod mapping. Handle nodebox.

This is the result inside freecad:

https://www.dropbox.com/s/liznoix6ezkx9uy/freecad.png

Basically, i have the whole problem solved here. FreeCAD can export the model in various kinds of formats. Blocks can be edited, etc.

To export a map piece from minetest :

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

/minetest <filename> <x1> <y1> <z1> <x2> <y2> <z2>

To import into FreeCAD :

Edit this line:

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

# replace filename - needs a beter interface
map = importvolumefile("c:/minetest/minetest-0.4.10/worlds/aldo/teste.vol")

"c:/minetest/minetest-0.4.10/worlds/aldo/teste.vol" is a fully qualified filename that points to a volume that i exported in my harddisk. Replace it with a correct fully qualified path name that points to the correct file inside your computer.

Cubes might happend to be mirrored/inverted, coords might happen to be rotated (x vs y, x vs z etc). Those small bugs need to be fixed by tests. First thing is to pupulate the "blockmapping" array in the lua source code. The blockmap has a simple structure, ["<registerednodename>"] = <value>. Any value above 0 will become a block inside minetest. The is scale is so that each block (node) inside minetest becomes a 10mm x 10mm x 10mm cube inside freecad. The scale can be changed by adding scale values to the importvolumefile call.

Your phone or window isn't wide enough to display the code box. If it's a phone, try rotating it to landscape mode.

Code: Select all

p = importvolumefile(<filename>, [<xscale>, [<yscale>, [<zscale>]]])

[prestidigitator]

Here's an example of a pyramid such as you were trying to export above.

[prestidigitator]

Fully released my BlockExport mod.

Wiki: http://wiki.minetest.net/Mods/BlockExport
Forum: https://forum.minetest.net/viewtopic.php?t=9948
GitHub: https://github.com/prestidigitator/minetest-mod-blockexport.git

[spin]

WHOA GUYS :O
I'll test this ASAP and post results, working on a lesson plan now (deadline).

[aldobr]

FreeCAD deals with solid geometry and has a fully constuctive solid geometry system. This is quite printer friendly. If the slicer needs a fused solid made out of the cubes i can easily make FreeCAD fuse the blocks. But this tends to be costly. I still need to implement a menu system inside FreeCAD and a better interface for Minetest. Plus i need to develop a way to export nodebox information (So as to print stairs for one). But this is a more involved development. We might arrange something. Current code is GPLv2.

[aldobr]

Continued development here :

viewtopic.php?f=9&t=9949

[spin]

For completeness: Blender Cycles render from a piece of Minetest map.

full message in screenshots thread: viewtopic.php?f=3&t=156&start=2450#p151540

[Inocudom]

For completeness: Blender Cycles render from a piece of Minetest map.

full message in screenshots thread: viewtopic.php?f=3&t=156&start=2450#p151540

Impressive. Have you ever tried this with a server?

[spin]

Impressive. Have you ever tried this with a server?

It's an .mts file exported with WorldEdit, and then ran over the mt2obj script (link to github above). Should work, but do try.

[Excalibur Zero]

I tried using sfan5's mt2obj converter, however I couldn't find out how to get the script to work. When I tried to run the script it just printed a few lines of text and stopped. (http://i.imgur.com/85PGHwq.png) How exactly do you use the script?

[aldobr]

You need to give a filename as parameter

[spin]

I tried using sfan5's mt2obj converter[...]How exactly do you use the script?

I do it like so:
-place your mts map file exported from Minetest with Worldedit (check commands) in mt2obj script's folder
-open Windows command line
-go to the directory you have the script in (using cd to change directory, dir to display contents)
-execute the script by typing either:
- - python mt2obj.py yourmapfile.mts
- - whole python path, like C:\Python27\python.exe mt2obj.py yourmapifile.mts
- import resulting .obj to Blender (involves waiting :/)

Good luck.

[spin]

In the testing I see that day/night cycle restricts visibility, and additional time has to be spent to set up lighting, and this makes classes time spent less effective.

Is there a way to remove or limit the night/day cycle?

[Topywo]

In the testing I see that day/night cycle restricts visibility, and additional time has to be spent to set up lighting, and this makes classes time spent less effective.

Is there a way to remove or limit the night/day cycle?

Frome minetest.conf.example
# Interval of sending time of day to clients
#time_send_interval = 5
# Length of day/night cycle. 72=20min, 360=4min, 1=24hour, 0=day/night/whatever stays unchanged
#time_speed = 72
# Length of year in days for seasons change. With default time_speed 365 days = 5 real days for year. 30 days = 10 real hours
#year_days = 30

So copy in your minetest.conf file this line:

time_speed = 0




Edit: some copy/paste typo...

[spin]

[...]time_speed = 0

Awesome, thanks!