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Pictured to the left is Joe, a character that

was created completely parametrically.

All his parts were made using either nurbzor patches, which are new v. 3.0 features.

In this article we summarize how to modeleach part. However, we also need to point

out that much of it is art and there is no

exact way of describing it. Thus, in somecases we simply show you how we did it

and leave it up to you to decide the specificdetails. If your Joe ends up looking

somehow different than ours, do not be

concerned. It will certainly be normal.

B. Creating a pair of pants with nurbz skinning

You will next model Joes pants by skinning source profiles alongpath lines and converting the resulting object to a nurbz object.

Again, you will only create one leg and will then Copy-Mirror it tomake the other leg.

Working in Front and Right views, use theVector Line tool to draw four paths, as shown

(B1, B2). Keep in mind that each vertex willeventually become a control point of the nurbz

surface, so keep the number of points fairly low.

To create a source profile at the lower endof the paths, turn on Snap to Point and with the

Vector Line tool draw a four-sided shape, bydrawing from end point to end point (B3, B4).

Turn on Snap to Midpoint and with the

Insert Point tool click on each of the segments ofthe previously drawn profile. You may also want

to turn on the Show Points option in the WireFrame Options dialog to be able to see yourpoints better (B3 , B4).

With the XY reference plane active, movethe newly inserted points to transform the profile

into a circular shape, as shown (B3, B4).

A. Creating a collared shirt with patches

Start by generating a simple cuboid,sitting on the XY plane (A1).

Activate the YZ reference plane and draw two lines

on it (A1). In the Trim/Split dialog select Split With Line and

Stitch. With the Trim/Split tool active, click on the cube

and on one of the lines.

Repeat the operation with the other line.This effectively inserts rectangles to the cube, as in A2.

With the Patch Attach tool detach faces along the

seam, in the neck, and in the armhole. With Delete remove the detached faces (A7).

With the Edit Controls tool edit the patch.

Use the Smooth Corner option to adjust individualcontrols without affecting the neighbors (A8).

Copy-Mirror the half shirt to the other side anduse the Patch Attach tool with topological level at

Segment to stitch the two halves.

Your final shirt should be as shown(A9).

A1 A2 Set topological level to Face, in the Pick Options

dialog select Clicking Inside Boundaries,in the Extrusion/Convergence Options dialog select

Perpendicular To Surface,and in the Status Of Object dialog select Keep.

With the Derivative 3D Extrusion tool click on the top

face, then on the side face of the top portion of the cube.Two cubes are derived, one from each of the faces you clicked on.

Scale down the top faces of the newly created cubes (A3).

Union the new cubes to the body of the original cube (A3). Generate one more cube on top of the side cube,

scale its top face, and Union it (A3). Repeat the previous operation

and extend the neck (like a collar)

and the arm of the shirt (A4 , A5).You have just constructed a cage or arough approximation of half of the shirt.

Note that the shirt is open at its front.

You will next convert this cage to apatch surface.

In the Patch Derive Optionsdialog select Bezier, Smooth,

In, and Equal Portions. With the Patch Derive toolclick on the cage object (A6).

In the Patch Attach And Stitchdialog select Detach. Topological level

is still at Face.

A3

A4 A5

A6 A7

Using the same technique you will also create the

t-shirt, inside the open shirt you just modeled.Note that the only differences are in the shape and

in that one is open while the other is closed.

Repeat these steps to also draw a profile at the top end of the

paths and two more between the two ends. Make sure all the profiles

are drawn in the same direction and that their first points line up.

In the Skin dialog select Nurbz and set both Length andDepth Degree to 3. In the Skinning Along Path box, # OfSources and # Of Paths should both be 4.

With the Skin tool active click on the sources and on the paths.

Once a skinned nurbz is gener-

ated for the leg, use the Edit Controls

tool to refine the shape of the leg (B5). Select the One Copy modifier and

with the Mirror tool make a reflectedcopy of the leg, as shown (B6).

You may wish to apply some more

adjustments to the shapes to make thelegs look asymmetrical.

C. Creating the boots

The next task is to model the boots. They will also

be constructed as skinned nurbz.

Again, working in Front and Right views, with

the Vector Line tool draw four paths (C1, C2).

Keep the lower points of the paths on the XY plane(X axis in projection), which will make it easier to

draw the source shape for the sole.You may also make the side paths symmetrical;

draw one and then copy-mirror it, as shown (C2).

In Top view, with the Vector Line tool, draw theprofile for the boots sole (C5). Use Snap to Point

as needed and draw an elliptical shape. Draw three more sources. Snap to points on

the paths and draw 4-sided shapes; then derive

tangent c-curves from them (C5). With the Skin tool and Nurbz on in its dialog,

select the sources and then the paths, deriving askinned nurbz, as shown (C6).

With the Derivative Surface Object tool derive

a shape from the bottom end of the boot andextrude it to derive a sole (C7).

Finally, create the laces as a nurbz axial sweepwith caps at both ends (C7 , C8). Draw the path by

snapping on the boot; the source is a little square.

byD

avidAnderson

A8

A9

B6

B1 B2

B3 B4

B5

C5 C6

C3 C4

C1 C2

C8

C7

Modeling Joe with nurbz and patchesModeling Joe with nurbz and patches

40 | informZ | June 1999 | autodessys, Inc.

7/31/2019 Modeling Joe

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E. Creating the head with nurbz

The head will be derived from a set of profiles, which will be used as

control lines to derive a nurbz object. The hardest part of this

modeling task is drawing the profiles, which you will do first.

On Top view and with Grid Snap on,

draw the rough outline of the hand (D1). With the 3D Extrusion tool click the

shape you drew to turn it into a solid (D2). With the Insert Segment tool, insert

five segments (1-2, 2-3, 4-5, 5-6,

and 3-6), as shown (D3).

Working on Top view, draw three

straight lines, as shown (D4). In the Trim And Split Options dialog

select Split With Line and Stitch . With the Trim/Split tool click on the

hand and on one of the lines.

Repeat the operation with the other twolines.

The result should be as shown(D5).

You will next manipulate and move some ofthe segments or points of the of the hand to

soften its shape, as shown(D6, D7). Move the top middle faces of the palm

upwards.

Move the bottom segments of thefingertips upwards.

Scale down (make smaller) the endface of the thumb tip.

Working on a Right view, draw the side profiles (front

and back) of a human head (E1). Then, working on a Frontview draw the side profile of a human head (E2). Note that,

for symmetry, it suffices to draw only one side. Theseprofiles will only be used as guidelines for deriving the other

profiles. They will not be used directly for the nurbz object.

You will next need to adjust the shapes of the circles to the shapesof the front and side profiles you drew earlier. This is a standard

procedure applied with the Independent Scale tool.

1 2

Referring to the Front view detail shown (E5),with topological level set to Point, frame select thepoints of a circle on one side of its center. Then with

the Independent Scale tool click on 1, 2, and 3.

Do the same for the points on the other side ofthe circle. Do this for all the circles (E7).

You also need to adjust the shape of the circlesworking on a Right view. Given the symmetry you

can do this in one step(E8).

Working in Top view, draw an 18 point circle, with itscenter roughly at the center of the head (E3). Before you draw,

turn on Ortho Snap, which will position the points of the circleproperly. Draw the circle at the lower end of the head.

Select the Multi-Copy modifier and in its dialog set # OfSteps to 15 and select Divide Distance.

Working in Right (or Front) view, with the Move tool click

on the circle and then on the top end of the profiles. Thisproduces 15 copies of the circle, positioned horizontally at

equal distances from each other (E4).

D1 D2

D5

D4

E7 E8

E1 E2

D. Creating the hand with patches

For the hand, you will construct a cage and will convert it to a patch.

Joes palm will have four fingers. The only reason for this is to underline

the sketchy nature of the character you will be modeling.

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3

2

1D3

D6

You will next create a forearm for the hand.

In the Extrusion/Convergence Optionsdialog select Perpendicular To Surface;

from the Heights menu selectGraphic/Keyed .

With the Derivative Extrusion tool select the

middle back face of the palm (highlighted in D7).

Extrude to a distance roughly as shown in D8. Delete the Topology of the two faces where

the two objects touch. With the Stitch tool click on the two objects to

stitch them into one.

Working on Top view draw a line to use for

creating a third joint on the hand (D11). Trim and Stitch it to the hand, as shown (D11).

You next want to manipulate the points of thecage to make the shape smoother and prepare it

for the generation of the patch object. Just shapethe hand as you like it. You may, of course,

observe how we did it and follow the examples.

After this process is completed, you are ready toderive patches from it.

In the Patch Derive Options dialog selectBezier, Smooth, In, and Equal Portions.

With the Patch Derive tool click on the cage.A patch object is generated, as shown(D16).

After it is derived you can still adjust its shape withthe Edit tools.

D9

D10

D11

D12

D13

D14

D8

D7

Select the circle (at the Object level) and thenclick on 1, 2, and 3.

The adjusted circles should be as shown(E7, E8).

At this point, you will individually adjust some more

points to break their flatness and to better sculpt

characteristics of a human face, such as eye sockets,

nose, etc.. You do this with whatever tools you prefer.Some of the points should be transformed in groups(by frame-picking them) and some individually.

Use our illustrations as guides(E9 - E12).

When the control lines are shaped to yoursatisfaction, select them with the Nurbz tool to derive

the head. In its dialog set Length and DepthDegree to 2 and turn on both Start and End Caps.This will be an iterative process. If you are not happy

with the initial shape of the head, Undo it, go back andmake adjustments to the control lines, and then derive

the object again. However, even after the head hasbeen constructed you can use the Edit Controls or Edit

Surface tools to further sculpt its shape.

For example, note how we pulled the ears out of thehead (E13, E14). You may actually wish to edit by

previewing the form in a shaded mode, such asQuickDraw or OpenGL. When you do, make sure you

have sufficient facet resolution to display smoothly.

To create the hair, draw a vector line from oneside of the head to the other by snapping to points on

the head. Then make a few rotated copies, adjust theirindividual points as necessary, and use them to derive

a nurbz object, as shown (E17 - E19).

Again, more adjustments can be made after the objectis generated, using the Edit tools.

For eyes, create a couple of spheres at theappropriate size. Make the eyebrows as nurbz

sweeps (E20) and position them on the head.

E3

E4

E9 E10

E11 E12

E13 E14

E15 E16

E17

E18 E19

E20D15

D16

autodessys, Inc. | informZ | June 1999 | 41