PREPARATION OF THREE-DIMENSIONAL MODEL FOR 3D PRINTING

Predstavili bomo postopek priprave trirazsežnega modela, opisanega v podatkovnem zapisu STL za slojevito tiskanje s 3D-tiskalnikom. Postopek v angleščini imenujemo tudi "slicing" in je že implementiran v nekaterih komercialnih in odprtokodnih rešitvah. Preučili bomo temeljne algoritme in procedure, s katerimi lahko zasnujemo takšno rešitev. Nato jo bomo implementirali in preizkusili. Posvetili se bomo izgradnji topologije mreže iz neurejenega seznama trikotnikov v standardnem teselacijskem jeziku STL (ang. Standard Tesselation Language), ki jo bomo razrezali na uniformno debele vzporedne plasti s koračnim algoritmom. Nato bomo v obrisih posameznih plasti določili pot tiskanja po obrisnem in črtastem vzorcu. Potem bomo poiskali najbližjo pot skozi povezane segmente poti z uporabo štiriškega drevesa in jo zapisali v formatu G-code tako, da bodo režijske poti med posameznimi segmenti poti kar najkrajše. Implementacijo bomo zasnovali v jeziku Python in jo preizkusili na napravi Prusa Mendel 2. generacije.In the following thesis we will describe the process of preparation of 3D models described in standard tesselation language STL (Standard Tesselation Language) for layered 3D printing. The process is also known as “slicing” and is already implemented in various commercial and open-source solutions. We will describe fundamental algorithms and procedures that are necessary for implementation of such a solution. The procedure will be presented and implemented in the following steps. Firstly the STL will be parsed into a disconnected mesh of triangles. In the next step we will construct the topological information of the mesh. After that the model will be sliced with uniform slice thickness using the marching algorithm for contour creation. Each slice will be filled with contour offsets and connected parallel line pattern. After that we will try to find an optimal way of printing the produced path using quad trees so that travel moves between connected path segments will be as short as possible. In the end the result will be presented in G-code format. The solution that implements the mentioned procedure will be written in Python programming language and tested on a device Prusa Mendel of 2nd generation