Tutorial: How to Metanurbize Extruded Curvilinear Polygons


TUTORIAL: How to Metanurbize Extruded Curvilinear Polygons

                                    P  R  E  M  I  S  E

The goal is to Metanurbize Extruded Curvilinear Polygons with Lightwave © Modeler, of Newteck 
Inc. ©.  Sometimes,  when you  are building  3D objects,  it is necessary to metanurbize some 
extruded curvilinear polygons. This operation, apparently so easy, hide some snare. Therefore 
you must proceed in a little unusual way to obtain a satisfactory result.  Probably there are 
different,  but as valid,  ways too,  but the one we are going  to examine is helpful also to 
understand  better  this 3D program.  This tutorial  is good either for Pc  or  for MacIntosh 
computers.  Click with mouse on small picture near the words and you can see them more large.

                                 P  R  O  C  E  D  U  R   E


This  tutorial  will  be  made  on  a polygonal extruded 
circle.  This for two motives: because the circle is the 
most full  existing curve  and  because  it is  the most 
difficult curvilinear polygon  to metanurbize  after its 
extrusion. Open your Lightwave Modeler ©, go to "Create" 
menu,  click on "Disc",  and  after open "Numeric" Panel 
(from keyboard "N"). Create a Circle, perpendicular to Z 
Axis, with a radius cm.50 long and with 36 Sides. But to 
metanurbize it with "TAB" key, it is necessary that your 
circle is built with triangular  or  quadrangolar faces, 
while now it is formed from one single polygon.


 Start  trying  to subdivide  it  automatically  with the 
 option "Construct/Subdivide/Fast-Triple-Fan.


Extrude it:  click on  "Multiply/Extrude" (from keyboard 
"CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
and insert the value of cm.5 for "Z" Axis.


 Metanurbize all,  pressing "TAB" key,  and after convert 
 it again, with "Construct/Convert/Freeze" (from keyboard 
 "CTRL+D"), in polygons. The result is quite horrible.


Try then  to subdivide  it automatically with the option 
"Construct/Subdivide/Fast-Triple-Traverse".


 Extrude it:  click on  "Multiply/Extrude" (from keyboard 
 "CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
 and insert the value of cm.5 for "Z" Axis.


Metanurbize all,  pressing "TAB" key,  and after convert 
it again, with "Construct/Convert/Freeze" (from keyboard 
"CTRL+D"), in polygons. The result is again horrible.


 Try then  to subdivide  it automatically with the option 
 "Construct/Subdivide/Triple" (from keyboard "SHIFT+T").


Extrude it:  click on  "Multiply/Extrude" (from keyboard 
"CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
and insert the value of cm.5 for "Z" Axis.


 Metanurbize all,  pressing "TAB" key,  and after convert 
 it again, with "Construct/Convert/Freeze" (from keyboard 
 "CTRL+D"), in polygons. The result is always horrible.


Try to proceed  in a different way.  In "Polygons" (from 
keyboard  "CTRL+H")  mode,  select  all  your  polygonal 
circle.  Remove its only single polygon,  but let intact 
its  points,  with "Construct/Reduce/Rem Polygons" (from 
keyboard "K").


 Go in "Points" mode (from keyboard "CTRL+G")  and select 
 with mouse, in an orderly way and sequentially, the four 
 lateral points on the left,  starting from the 2 central 
 points,  first the one low  and  after the one high, and 
 ending  with  the 2 external points,  first the one high 
 and after the one low. Now create the first quadrangular 
 polygon  with "Create/Elements/Make Pol"  (from keyboard 
 letter "P").


Go on  with the other points,  following  the same exact 
order in the points selection,  four at a time for every 
new polygon.  Create so at last  a new poligonal object, 
as the one on the right.


 Extrude it:  click on  "Multiply/Extrude" (from keyboard 
 "CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
 and insert the value of cm.5 for "Z" Axis.


Metanurbize all,  pressing "TAB" key,  and after convert 
it again, with "Construct/Convert/Freeze" (from keyboard 
"CTRL+D"),  in polygons.  The result is  a little better 
than the others, but not good enough yet.


 Erase all.  Come back to your starting circle and delete 
 the poligons  with "Construct/Reduce/Rem Polygons" (from 
 keyboard "K"). In "Points" mode (from keyboard "CTRL+G") 
 select only the highest point of your circle on "Y" Axis 
 and click down your screen on "Copy" (from keyboard "C") 
 then  on "Paste" (from keyboard "V").  After this select 
 "Modify/Move"  (from keyboard "T"), open "Numeric" panel 
 (from keyboard "N")  and  set  the value  of "Y" Axis of 
 selected point at cm. -50.  Press "Apply"  and  you will 
 create in this way a central point into your circle.


Go in "Points" mode (from keyboard "CTRL+G")  and select 
with mouse,  in an orderly way and sequentially, the two 
lateral points on the left, first the one low  and after 
the one high,  and at last the central point, as you can 
see in the pic on right. Now create the first triangular 
polygon  with "Create/Elements/Make Pol"  (from keyboard 
letter "P").


 Go on  with the other points,  following  the same exact 
 order in the points selection, three at a time for every 
 new polygon.  Create so at last  a new poligonal object, 
 as the one on the right.


Extrude it:  click on  "Multiply/Extrude" (from keyboard 
"CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
and insert the value of cm.5 for "Z" Axis.


 Metanurbize all,  pressing "TAB" key,  and after convert 
 it again, with "Construct/Convert/Freeze" (from keyboard 
 "CTRL+D"),  in polygons.  The result is insufficient and 
 not good enough yet.


Let we see now what is  the right solution.  Start again 
from beginning  and  create  again  your circle with the 
same exact starting values. After go to "Polygons" (from 
keyboard "CTRL+H") mode  and  select  all your polygonal 
circle.  Remove its only single polygon,  but let intact 
its  points,  with "Construct/Reduce/Rem Polygons" (from 
keyboard "K"). In "Points" mode (from keyboard "CTRL+G") 
select all the 36 circular points you see on your screen 
and click down your screen on "Copy" (from keyboard "C") 
then  on "Paste" (from keyboard "V").  After this select 
"Modify/Stretch" (from keyboard "H"), open the "Numeric" 
panel (from keyboard "N")  and  set the horizontal value 
on 87,5 and the vertical value on 87,5,  perpendicularly 
to "Z" Axis.  Press "Apply" and so you will create a new 
serie of inscribed points into the previous ones.


 Always in "Points" mode  (from keyboard "CTRL+G")  first 
 deselect  all selected points.  After select only the 36 
 internal circular points,  clicking  with mouse on them, 
 one  at  a time,  in  an orderly way  and  sequentially, 
 clockwise,  starting  from the left lateral point.  Take 
 care you don't forget to select some point! After create 
 the internal circular polygon with "Create/Elements/Make 
 Pol" (from keyboard letter "P").


After you must create the external quadrangular polygons 
in regard  to the internal circular polygon in this way: 
Go in "Points" mode (from keyboard "CTRL+G")  and select 
with mouse, in an orderly way and sequentially, the four 
lateral points on the left, starting from the 2 external 
points,  first the one low  and  after the one high, and 
ending  with  the 2 internal points,  first the one high 
and  after  the one low.  As  you  will have selected in 
right mode these 4 points, then you can create the first 
external quadrangular polygon with "Create/Elements/Make 
Pol" (from keyboard letter "P").


 Go on  with the other points,  following  the same exact 
 order in the points selection,  four at a time for every 
 new polygon.  Create so at last  a new poligonal object, 
 as the one on the left,  consisting  of an external ring 
 of quadrangular polygons  linked  with internal circular 
 polygon.


Extrude it:  click on  "Multiply/Extrude" (from keyboard 
"CTRL+E"), then open "Numeric" Panel (from keyboard "N") 
and insert the value of cm.5 for "Z" Axis.


 Metanurbize all,  pressing "TAB" key,  and after convert 
 it again, with "Construct/Convert/Freeze" (from keyboard 
 "CTRL+D"),  in polygons.  The result is now really good! 
 At last  you have metanurbized  successfully an extruded 
 curvilinear polygon!

I have written this page in Italian language and after I have translated it in English language.
If you find some my translation's error, excuse me and send me an e-mail with the correct version. Thanx !!
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