Artifacts when voxelizing mesh cube

[mhaemmerle]

When trying to voxelize a simple cube exported from Blender, this is the result when viewed in Magicavoxel (version 0.99.6.2):

If I e.g. slightly taper the 4 top points of the cube the artifacts will vanish - though leaving me with one or more steps in the voxelized result (where the side faces of the cube have been). Also the artifact in the top is still there:

To reproduce:

• open Blender (I used version 2.8), create default mesh cube at 0, 0, 0 and export as binary Stl
• change filename from 'model.stl' to the one exported from blender and run (master branch)

I can't attach Stl files here, but this is the same cube exported as text Stl:

solid Exported from Blender-2.80 (sub 75)
facet normal -1.000000 0.000000 0.000000
outer loop
vertex -1.000000 -1.000000 -1.000000
vertex -1.000000 -1.000000 1.000000
vertex -1.000000 1.000000 1.000000
endloop
endfacet
facet normal -1.000000 0.000000 0.000000
outer loop
vertex -1.000000 -1.000000 -1.000000
vertex -1.000000 1.000000 1.000000
vertex -1.000000 1.000000 -1.000000
endloop
endfacet
facet normal 0.000000 1.000000 0.000000
outer loop
vertex -1.000000 1.000000 -1.000000
vertex -1.000000 1.000000 1.000000
vertex 1.000000 1.000000 1.000000
endloop
endfacet
facet normal 0.000000 1.000000 0.000000
outer loop
vertex -1.000000 1.000000 -1.000000
vertex 1.000000 1.000000 1.000000
vertex 1.000000 1.000000 -1.000000
endloop
endfacet
facet normal 1.000000 0.000000 0.000000
outer loop
vertex 1.000000 1.000000 -1.000000
vertex 1.000000 1.000000 1.000000
vertex 1.000000 -1.000000 1.000000
endloop
endfacet
facet normal 1.000000 0.000000 0.000000
outer loop
vertex 1.000000 1.000000 -1.000000
vertex 1.000000 -1.000000 1.000000
vertex 1.000000 -1.000000 -1.000000
endloop
endfacet
facet normal 0.000000 -1.000000 0.000000
outer loop
vertex 1.000000 -1.000000 -1.000000
vertex 1.000000 -1.000000 1.000000
vertex -1.000000 -1.000000 1.000000
endloop
endfacet
facet normal 0.000000 -1.000000 0.000000
outer loop
vertex 1.000000 -1.000000 -1.000000
vertex -1.000000 -1.000000 1.000000
vertex -1.000000 -1.000000 -1.000000
endloop
endfacet
facet normal 0.000000 0.000000 -1.000000
outer loop
vertex -1.000000 1.000000 -1.000000
vertex 1.000000 1.000000 -1.000000
vertex 1.000000 -1.000000 -1.000000
endloop
endfacet
facet normal 0.000000 0.000000 -1.000000
outer loop
vertex -1.000000 1.000000 -1.000000
vertex 1.000000 -1.000000 -1.000000
vertex -1.000000 -1.000000 -1.000000
endloop
endfacet
facet normal 0.000000 0.000000 1.000000
outer loop
vertex 1.000000 1.000000 1.000000
vertex -1.000000 1.000000 1.000000
vertex -1.000000 -1.000000 1.000000
endloop
endfacet
facet normal 0.000000 0.000000 1.000000
outer loop
vertex 1.000000 1.000000 1.000000
vertex -1.000000 -1.000000 1.000000
vertex 1.000000 -1.000000 1.000000
endloop
endfacet
endsolid Exported from Blender-2.80 (sub 75)

Is this a bug in VoxSurf or a limitation in the algorithms used?

[mhaemmerle]

I packaged the blender file and exported Stl in the zip file here:
issue_attachment.zip