Upload
widgetdog
View
215
Download
0
Embed Size (px)
Citation preview
7/31/2019 Modeling Joe
1/2
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
2/2
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.
6
54
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