PolyMesh Modeling and Subdivision Overview Tutorial
written by olivier amrein
website: skol - effects visuels
modified by: Ed Harriss



This tutorial is intended for people who already have a working knowledge of XSI

This tutorial works with
SOFTIMAGE|XSI 1.5 and above, only.
Be sure your in the "model" module (press 1)
I often work in Hiddenline mode which suits me best

This is what we are going to achieve:

let's start with a marvellous 6-sided cube: Get->Primitive->Polygon Mesh->Cube

select the 2 front edges (by holding E-key and clicking on them)
note: you can also write edge[7,10] in the selection field (it should work)

note : E-key is to switch in edges mode, Y-key in poly-mode (with rectangular selection), U-key is raycasting selection poly mode

now we will subdivide the edge: there are 2 methods:

- in the menu Modify-> Poly Mesh-> Subdivide Edges (Evenly)
- or pick point in the selected edge and by holding ALT and right mouse button (RMB)...
you get a very cool "Contextual Menu" ...where you find our Subdivide Edges (evenly) command

select the newly created edge and move it a bit in the front

scale it in x to 0.6

we now have on each side a pentagon ... with non coplanar points... we are going to add a new edge to correct this.
back in object mode (often the spacebar will do it) and select the onject
do the Contextual menu trick (right mouse button, a.k.a. Magik-menu) and select Add Edge Tool
(or press \ (which doesnt work if you have a swiss keyboard))
(or go in the menu Modify->Ploy.Mesh->Add Edge Tool)
select the 2 points and add the edge

do the other side too
hum...I'm pretty lazy :o)

in the right view draw a curve (Create->Curve-Draw CV NURBS) a bit like this one :

select the front poly (for instance, use the raycast method (U-key))

and do an Extrude Along Curve ...
select the curve you just drew and set the SubDivs to 6 ...you should get this figure:

now to the tail ...
select the extreme back poly and do a Bevel Component (again, using the Magik-menu) on it (around 0.4)

note : dont forget to deselect previously selected component or you'll get weird results

with the back poly still selected do an Extrude Along Axis:
length 8
subdivs 6
in the tranform panel:
sclae x=0.1 y=1.6 z=0.1
rot x=40 y=60 z=30
fianlly turn the per subd off

do you get something like fig8 ?

have you noticed Iswitched to shaded mode? ;)


reselect the object and select the Split Edge Tools and
use the middle button (Split All Parallel Edges) on the edges shown in those 2 fig.

this is a good way to add points for further refinement, isn't it?


select the 2 lower front vertex and Bevel them (0.5)...

now let's subdivide this a bit:
go to part II

no 2000 - by olivier amrein
website: skol - effects visuels
modified by: Ed Harriss