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