MODELING FOR 3D PRINTING
 
THERE ARE SOME THINGS TO KEEP IN MIND
WHEN CREATING 3D MODELS FOR PRINTING.
 
FOLLOW THESE GUIDELINES
 TO MAKE SURE YOUR MODEL PRINTS NICELY.
 
UNITS
MAKE SURE YOUR SOFTWARE IS USING MILLIMETERS, NOT METERS OR INCHES.
TO DOUBLE CHECK (OR IF YOU WANT US TO SET THE SIZE FOR YOU)
ALWAYS LET US KNOW WHAT SIZE THE MODEL SHOULD BE.
 
NO SMOOTHING
ALL 3D MODELS ARE MADE FROM LITTLE TRIANGLES FORMING A MESH.
MOST 3D SOFTWARE USES "SMOOTHING" TO MAKE THINGS LOOK NICE...
BUT THIS SMOOTHING IS USELESS FOR 3D PRINTING
UNLESS YOU APPLY THE SMOOTHING TO THE MESH.

WE OFTEN RECEIVE MODELS CONTAINING (FOR INSTANCE) SPHERES
THAT ARE CONSTRUCTED OUT OF 32 OR LESS PLANES.
THE MODEL LOOKED NICE IN THE DESIGN PROGRAM, BUT THE ACTUAL
MESH IS NOT DETAILED ENOUGH TO MAKE A NICE SMOOTH SPHERE.
 
SO SWITCH OFF ALL SMOOTHING OPTIONS
AND MAKE SURE YOU USE PLENTY OF POLYGONS TO CREATE
SMOOTHLY CURVED SURFACES - BUT DON'T EXAGGERATE,
AS USING TOO MANY POLYGONS WILL SLOW YOUR SYSTEM DOWN.
 
AS A RULE OF THUMB, AN AVERAGE DISTANCE BETWEEN TWO VERTICES
OF 0.2 - 0.3 MM IS USUALLY FINE. LARGER DISTANCES LEAD TO VISIBLE EDGES
IN THE PRINT, SMALLER DISTANCES CAN LEAD TO AN EXCESSIVELY "HEAVY" MODEL.
 
WATERPROOF MESH
YOUR MODEL SHOULD CONSIST OF A SINGLE CLOSED MESH
 WITHOUT ANY HOLES (MISSING POLYGONS).
 
THIS DOES NOT MEAN THERE CAN BE NO HOLES IN YOUR MODEL,
BUT IF THERE ARE, THESE HOLES MUST ALL BE PART OF THE ONE
SINGLE MESH (SO THERE ARE INSIDE WALLS TO THE HOLES).
 
SO THE MESH CAN BE ANY SHAPE, AS LONG AS IT COULD BE
"FILLED WITH WATER WITHOUT LEAKING".
 
INSIDE INSIDE & OUTSIDE OUTSIDE
ALL THE TRIANGLES IN YOUR MODEL HAVE AN INSIDE AND AN OUTSIDE SURFACE.
MAKE SURE ALL INSIDES ARE ON THE INSIDE, AND ALL OUTSIDES ON THE
OUTSIDE OF THE MESH. IN TECHNICAL TERMS: NO FLIPPED NORMALS PLEASE.
 
NO LOOSE OR NON-MANIFOLD VERTICES
THIS MIGHT SOUND QUITE TECHNICAL.  DON'T WORRY, WE'LL KEEP IT SIMPLE.
ALL THIS MEANS IS THAT THE MODEL MUST CONSIST OF A SINGLE MESH ONLY.
SO NO LOOSE PLANES OR VERTICES FLYING AROUND OR INSIDE THE MODEL.
 
ALL THE EDGES CONNECTING THE VERTICES MUST ALL BE PART OF THE SINGLE MESH.
ANY CONNECTING EDGES THAT ARE NOT PART OF THIS "SKIN" MAY CAUSE
UNWANTED EFFECTS IN THE PRINTER SOFTWARE.
 
ALSO MAKE SURE THE MESH NEVER CROSSES ITSELF (SELF-INTERSECTION).
 
THE 45 DEGREES RULE
THIS RULE STATES THAT
THE MODEL'S SKIN SHOULD NOT LEAN OUTWARDS MORE THAN 45 DEGREES -
(SAME GOES FOR INWARDS IN CASE OF HOLLOW OBJECTS).
 
HERE'S WHY:
 
OUR PRINTERS WILL PRINT THE BOTTOM LAYER OF YOUR MODEL FIRST.
EACH NEXT LAYER HAS TO BE PRINTED ON TOP OF THE PREVIOUS LAYER.
IT CAN STICK OUT OVER THE SIDE A BIT, BUT NOT TOO MUCH !

FOR INSTANCE:
IF YOUR MODEL IS A SAUCER, THE SKIN IS LEANING OUTWARDS TOO MUCH.
EACH PRINTED LAYER WILL EXTEND OUTWARDS SO MUCH FURTHER THAN THE
PREVIOUS ONE THAT THERE WILL BE NOTHING FOR THIS LAYER TO PRINT ONTO.

ANOTHER EXAMPLE:
IF YOUR MODEL IS A STANDING FIGURINE WITH ITS ARMS HANGING DOWN,
THE PRINTER WILL START WITH THE FEET, THEN BUILD UP THE LEGS, KNEES,
ETCETERA, NO PROBLEM. HOWEVER, AT SOME POINT IT WILL START
PRINTING THE TIPS OF THE FINGERS  -  IN MID-AIR...

THIS DOES NOT MEAN THAT WE CAN NOT PRINT A SAUCER OR A FIGURINE,
 
BUT IT DOES MEAN THAT IN THOSE CASES WE WILL HAVE TO ADD A
SO-CALLED "SUPPORT STRUCTURE". THIS WILL PROVIDE A BASE FOR
THE PARTS OF THE MODEL THAT BREAK THE 45 DEGREES RULE.

SUPPORT STRUCTURES ARE REMOVED AFTER PRINTING.
MODELS THAT NEED A LOT OF SUPPORT WILL TAKE MORE TIME TO
PRINT AND ALSO TAKE MORE TIME TO "CLEAN" AFTER PRINTING.
THE PARTS THAT WERE TOUCHING THE SUPPORT STRUCTURE WILL BE
LESS SMOOTH AND LESS ACCURATE THEN THE REST OF THE PRINT.

PLEASE NOTE HOWEVER THAT ON OUR WELL-TUNED PRINTERS
WE CAN PRINT OUTWARDS AT AS MUCH AT 60 DEGREES WITHOUT NEEDING SUPPORT !
WE LIKE STRETCHING THE RULES... HOWEVER, IN THIS CASE IT WILL LEAD TO
LOSS OF PRINT QUALITY, SO BEST STICK TO THE 45 DEGREE RULE AS MUCH AS POSSIBLE.
 
TINY, THIN AND FLIMSY BITS
OUR PRINTERS CAN PRINT MINUTE DETAILS, BUT THERE ARE SOME LIMITATIONS WHEN
IT COMES TO TINY, THIN AND FLIMSY BITS LIKE TREE BRANCHES, POINTY EARS,
THIN WALLS AND SUCH. THIS HAS TO DO WITH THE SPECIFICATIONS OF OUR PRINTERS -
LET'S HAVE A LOOK AT THEM.

THE X-Y MOVEMENT PRECISION IS 0.01 MM (!) SO NO PROBLEM THERE.

VERTICAL PRINT RESOLUTION IS DETERMINED BY THE LAYER HEIGHT.
WE OFFER 4 DIFFERENT OPTIONS:
 
 - BUDGET RESOLUTION: 0.2 MM PER LAYER (= 5 LAYERS PER MM)
 - MEDIUM RESOLUTION (STANDARD): 0.15 MM PER LAYER (= 6.7 LAYERS PER MM)
- HIGH RESOLUTION: 0.1 MM PER LAYER (= 10 LAYERS PER MM)
- ULTRA-HIGH RESOLUTION: 0.05 MM PER LAYER (= 20 LAYERS PER MM)

FOR MOST PRINTS, MEDIUM RESOLUTION GIVES BEST PRICE/QUALITY RATIO.


  HORIZONTAL PRINT RESOLUTION (FOR THE X-Y PLANE) IS A BIT MORE COMPLEX.
 
 
ALTHOUGH THE MOVEMENT OF THE PRINT HEAD IS CONTROLLED WITH AN ACCURACY
OF 0.01 MM, THE MODEL IS BUILT OUT OF "LINES" THAT ARE 0.4 MM WIDE.
(WHICH IS THE SIZE OF THE HOLE IN THE PRINTER NOZZLE.)

SO IN AN OBJECT WITH THIN VERTICAL PARTS, OR A THIN-WALLED OBJECT LIKE A CUP
OR A VASE, THESE THIN BITS MUST HAVE A THICKNESS OF AT LEAST 0.4 MM.
(IN FACT, MAKE THOSE MINIMAL BITS 0.41 MM TO BE SURE, AS 0.4 SOMETIMES
TURNS OUT TO BE 0.3999 MM, IN WHICH CASE THE PRINTER WILL SKIP THIS PART...)

FOR THIN VERTICAL PARTS IT IS BEST TO STICK TO ONE OF THESE SIZES:
0.41 MM (SINGLE SHELL)  OR
0.81 MM (TWO SHELLS)  OR
1 MM OR MORE (TWO SHELLS (OR MORE) WITH INFILL).

THE DIFFERENCE BETWEEN HORIZONTAL AND VERTICAL RESOLUTION
MEANS THAT (FOR INSTANCE) IT IS POSSIBLE TO HAVE SOME RATHER FINE LETTERING
ON THE VERTICAL WALLS OF AN OBJECT, BUT THE SAME LETTERING WOULD NOT COME
OUT NICELY WHEN PRINTED HORIZONTALLY ON THE TOP PART OF THE OBJECT.
 
HOLLOW / SOLID
MOST "SOLID" OBJECTS ARE PRINTED WITH A "SHELL" FOLLOWING THE SHAPE
OF THE MESH, AND A "FILL" OF 20 - 25 %, WHICH MEANS THAT THE INSIDE IS
FILLED WITH INTERNAL WALLS INSTEAD OF A SOLID (100 %) FILL.
THIS SAVES A LOT OF PRINTING TIME (=COST).

IT IS ALSO POSSIBLE TO PRINT HOLLOW OBJECTS (0 % FILL).
IT IS EVEN POSSIBLE TO PRINT A TOP ONTO A HOLLOW OBJECT,
EITHER BY CURVING TOWARDS THE CENTRE OR BY "BRIDGING".

TO CREATE A HOLLOW OBJECT, YOU CAN MODEL IT AS IF IT WAS A SOLID OBJECT.
THIS WAY YOU DON'T HAVE TO WORRY ABOUT CREATING THE RIGHT WALL
THICKNESS IN YOUR MODEL - JUST TELL US WHAT THICKNESS YOU WANT
AND WE'LL TAKE CARE OF IT.

THIS ALSO WORKS FOR CUPS AND VASES - JUST TELL US TO PRINT WITH NO TOP.

OR YOU CAN CREATE A HOLLOW MODEL WITH YOUR OWN WALL THICKNESS(ES)
TO YOUR OWN SPECIFICATIONS, BUT THIS IS A BIT MORE TRICKY. IT'S UP TO YOU.
 
 
ORIENTATION

FOR EACH OBJECT THERE IS AN OPTIMAL ORIENTATION FOR PRINTING.
WE ALWAYS MAKE SURE YOUR MODEL IS PRINTED IN THE BEST WAY POSSIBLE,
WHICH MAY TURN OUT TO BE UPSIDE DOWN, SIDEWAYS,
OR EVEN LEANING UNDER A CERTAIN ANGLE, IF THIS (FOR INSTANCE) HELPS
TO SOLVE PROBLEMS WITH THE "45 DEGREES RULE".
 
WE WILL ALWAYS LET YOU KNOW IN ADVANCE IF WE THINK IT IS NECESSARY
TO CHANGE THE PRINTING ORIENTATION OF YOUR MODEL.