[OpenSCAD] Functional OpenSCAD, working with vertex data

NateTG nate-openscadforum at pedantic.org
Mon Jan 29 22:15:53 EST 2018


> I agree that some form mesh validation would be pretty handy, but I'm
> not well versed in relevant algorithms for that sort of thing.

It's super simple.   I'll just write it up and submit it on github.

> ... I've *heard* of delaunay triangulation, for
example, but have never attempted to implement it myself. ...

Delauney triangulation and voronoi diagrams are for things like finding
nearest neighbors.   Polygon triangulation involves different algorithms.  (
https://en.wikipedia.org/wiki/Polygon_triangulation )

I'll submit a simple stupid one on github.

> ... Projective transform is already possible using a 4x4 matrix though,
> right? ...

It is possible with 4x4 matrices but not supported in OpenSCAD.

https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Transformations#multmatrix

"...the fourth row is used in 3D environments to define a view of the
object. it is not used in OpenSCAD and should be [0,0,0,1]..."

(I thought it was too, but realized it wasn't after suggesting it as an
improvement in the 'bend algorithm' that uses intersections and multmatrix. 
https://github.com/openscad/openscad/issues/815 )

P.S.:

A 2-3 tree is a self-balancing tree.  It's a data structure for searchable
lists.

https://en.wikipedia.org/wiki/Self-balancing_binary_search_tree






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