WEEK 4 - NURBS SURFACES

For instance, if you want the object to be flat on one side, how many degrees do you revolve it by?

180

The UV coordinate system deals only with a

2D surface area

The curve can be revolved up to a maximum of how many degrees?

360

The XYZ coordinate system identifies points in Maya's

3D world space

If an object needs to fit in a corner, revolve it by how many degrees?

90

The Sculpt Geometry Tool is one of Maya's

Artisan brush tools

These tool work like paint brushes.

Artisan brush tools

This lets you create isoparms at the current position, effectively creating a subdivision of the surface.

At Selection

This creates isoparms between your choice of selected isoparms, or between all U or V isoparms.

Between Selections

For example, to create a ledge on a building, or the rolled edges on an upholstered chair use this tool.

Bevel

Use this tool to create an extruded surface with a beveled edge from any curve, including text curves and trim edges.

Bevel

This tool has various features beyond the simple Bevel operation. It creates a completely solid surface, including a cap on either end of the beveled curve. The surface will not break when you deform it.

Bevel Plus

Like curves, NURBs surfaces have these four things.

CVs, hulls, edit points and spans

Both Surfaces is the default for what option?

Create Curves For

This option for the Intersect Surfaces tool allows you to create curves on only the first surface selected (the target surface) or on both the target surface and the surface selected as the intersecting surface.

Create Curves For

You can view the UV directions and surface normal of a selected object by using

Display > NURBS > Surface Origins

Use this tool to create a surface by sweeping a cross-sectional profile curve along a path curve.

Extrude

This option for this command controls where the new isoparms will be inserted.

Insert Location

This is another way to create trim curves for future surface modification.

Intersect Surfaces

Use this tool to intersect one surface with another.

Intersect Surfaces

In other words, you create a series of curves that define the shape of an object, then BLANK these curves together as if you're stretching a canvas over a wire frame.

Loft

Use this to construct a surface that passes through a series of profile curves.

Loft

You can use this surface tool, for example, to create an airplane body or wings. You can also create intermediate areas between any two surfaces created with boundary curves.

Loft

The following tools found under the Surfaces menu in the Main Menu Bar:

Loft, Planar, Revolve, Extrude, Bevel & Bevel Plus

Enter a value in this box to reposition the isoparm.

Parameter box

This surface tool creates a trim surface from one or more planar curves.

Planar

This creates curves-on-surface (or trim curves).

Project Curve On Surface

Use this surface editing tool to project one or more curves onto one or more surfaces.

Project Curve On Surface

A list of surface editing tools and commands available under the Surfaces menu in the Main Menu Bar:

Project Curve On Surface, Intersect, Trim Tool, Insert Isoparms, Sculpt Geometry Tool

Use this tool to construct a surface by revolving a profile curve about an axis.

Revolve

Pick the first curve you want to loft, then

SHIFT-click to pick subsequent curves

This tool lets you manually sculpt NURBs surfaces quickly with the stroke of a brush.

Sculpt Geometry Tool

You simply paint the surface mesh using this tool to push or pull CVs to achieve the shape you want. The effect is similar to sculpting clay.

Sculpt Geometry Tool

The active view is not important if you project while this option is selected.

Surface Normal

This option lets you project a curve onto the selected surface in one view and then use the same curve to project onto additional surfaces in any other view.

Surface Normal

When creating an extruded surface choose

Surfaces > Extrude

Select this to insert the new isoparm.

Surfaces > Insert Isoparms

First, trim curves are creating using

Surfaces > Intersect

Once all profile curves are selected, for Lofting a curve, choose

Surfaces > Loft

While the profile curve is active, select this to build the surface.

Surfaces > Revolve

This tool is selected and the cylinder is clicked to display the trim grid.

Trim Tool

Use this tool to trim a surface while retaining specified regions of the surface and discarding others.

Trim Tool

For the Direction, enter

U or V

If you are inserting a V directional isoparm, you can only move along the

U parametric direction on the surface

If you are inserting a U directional isoparm, you can only move along the

V parametric direction on the surface

UV coordinates are not the same as the

XYZ world space coordinates

For example, if the front view is active, the curve is projected along which axis (the axis normal to the front view)?

Z axis

A surface has this and that parametric direction.

a U and a V

Move the pointer over a surface and Maya displays

a brush outline

Each patch has

a certain number of CVs, controlled by the degree of the curve

To use the Revolve tool, you first create

a curve that serves as the outline of the surface you want to construct

In addition to having UV directions, a surface also has

a front side and a back side

When you select an Artisan tool, the Maya pointer changes to

a paint brush

Clicking the brush on a surface creates

a stamp

The front side and the back side of a NURBS surface is determined by

a surface normal

A normal is

a vector that faces outward perpendicularly from a point on the front side of a surface

If the path curve changes direction abruptly, undesirable twisting of the cross section around the path might occur. If this happens,

add CVs to the path curve so its direction changes more gradually

If you turned on the Partial option in the Bevel Options window, click the curve or isoparm heading in the channel box to show

additional attributes for using only a subsection of the curve

This can be created by intersecting several curves.

an enclosed region

You do not necessarily need a single boundary curve to create a trimmed surface, however, you do need

an enclosed region

When you insert this, the Channel Box includes a Parameter box, as well as a Direction pop-up menu.

an isoparm

The profile curve can be any of these four things.

an open or closed curve, a surface isoparm, curve-on-surface, or trim boundary

How is a stroke created?

by dragging across the surface

The scheme for identifying positions on a curve or surface (parameterization) is the same except that surface points are

calculated in two dimensions (U and V)

To make a trimmed surface from a single closed curve, click on a

closed curve or surface isoparm and select Surfaces > Planar

Make sure the curve you want to use in a planar trimming operation is a

closed or planar curve, or that multiple curves form a closed region

When you use Revolve, you can choose whether or not the object

completes the revolution

A NURBS surface is essentially a

connected sequence of NURBS curves

Lofting is used most often to

create new surfaces from curves or primitive shapes, or to close open surfaces

To trim a surface, you need

curves-on-surface to use as trim curves

Leave history on if you plan to modify the trimmed surface by

deleting CVs

These of a NURBs surface cannot be moved.

edit points

Hulls are useful for selecting

entire rows of CVs

Sometimes you need to add this on a surface so you can edit surfaces to your specifications.

extra isoparms

Any curve can be revolved:

free curves, surface curves (isoparms), curves-on-surface, and trim boundaries

The last curve selected in a lofted surface is what color by default?

green

For instance, if you select a pair of isoparms and turn on Between Selections, where does Maya create the isoparm?

halfway between the pair

You cannot delete CVs on trimmed surfaces that were created without

history

By increasing or decreasing the radius of a brush stamp, you

increase or decrease its area of influence

To increase the number of CVs you can do two things.

insert extra isoparms or increase the degree of the surface

You can Shift-select more than one isoparm to

insert several isoparms

In addition to the components derived from curves, NURBs surfaces are also composed of

isoparms and patches

Clicking the trim grid selects the area of the surface to

keep

When creating an extruded surface, select the path curve

last

Isoparametric curves (or isoparms) are

lines running along the surface in the U and V directions, showing the shape of the surface as defined by the CVs

This surface is constructed from curve to curve in the order that you selected them.

lofted surface

A stroke is made up of

many overlapping stamps

You can create beveled surfaces from

normal 3D curves, isoparms, and surface edges

The Project Along option specifies whether the projection will be

normal to the active view or to the surface normal direction

Active View, the default, means that the projection

occurs in the direction of the normals in the active view

You can create trimmed surfaces using curves with

overlapping boundaries

The area enclosed by four adjacent isoparms is called a

patch

Each point on a curve or a surface has a

position value

The curve can be revolved by either

positive or negative amounts

When creating an extruded surface, you can select more than two

profile curves

These operations of the Sculpt Geometry Tool move the position of the surface's control vertices.

push, pull, smooth, relax and erase

You can perform five different operations using the Sculpt Geometry Tool:

push, pull, smooth, relax and erase

If you delete CVs on trimmed surfaces that were created without history, the surface

remains untrimmed

To insert isoparms on a surface, do this or that.

select and drag an existing isoparm to the desired position or select a point on the surface and drag

Look in the Help Line to verify your

selection

If you use a pressure sensitive graphics tablet and stylus, you can

set an upper and lower range for the radius.

CVs can be used to control the

shape of the surface

Bevel Plus also gives you various

style options for the bevel shape.

Curves-on-surface (or trim curves) are useful for

surface trimming, aligning, path animation, and other tasks

If you select many surfaces, the last selected is the

target surface

Surface normals are important for using certain modeling tools as well as for

texturing and rendering objects

The brush outline defines

the area affected by the tool

Instead of being limited by a closed 360 degree revolution, you can specify

the number of degrees

If you select Surface Normal, make sure you move the curve to

the outside of the surface

To create an extruded surface, select

the profile curve first then SHIFT-select the path curve

No matter how much pressure you apply to the stylus, the brush radius will not be larger or smaller than

the set limits

For example, if you select 10 surfaces, the first nine are intersected with which surface?

the tenth

In the toolbox, click the Show Manipulators tool

to manipulate the beveled surface

This type of planar surface is created as indicated by a grid that fills the curve.

trimmed surface

To loft a surface, you need at least

two profile curves or surface isoparms