Maya: Advanced NURBS and Poly Modeling

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Setting the Clipping Plane
You may have noticed your objects mysteriously disappearing.  The computer uses clipping planes to save memory. There is a cubic area where models exist, outside of that region they disappear.

In any of the modeling windows, especially persp  choose View->Camera Attribute Editor... 
     Under Camera Attributes:
     Adjust Far Clip Plane to a number higher than 10000.



Adding CVs to the End of a Curve
In the Modeling Module:

Pick the curve you would like to add points to. This adds to the end of the curve.

Use the Curves->Add Points Tool.

Hit Enter key to finish

If you want to add points to the beginning of a curve you will need to use Curves->Reverse Direction.



Adding Edit Points and CVs to the Middle of a Curve.
In the Modeling Module, using the object type button:

Hold the mouse over the curve, use the right mouse key to bring up the curve menu:
Choose Curve Point
Drag the curve point along the curve until it is in the desired position.

Use Curves->Insert Knot to add an edit point at the curve point location, a CV will be added nearby.

Curve Points can be used to detach curves as well with Curves->Detach.



Absolute Vs. Relative Transformations.
Have you noticed when you transform an object it moves exactly as input. This is an absolute transformation. For example: Rotate an object 90 degrees, then rotate it 10 degrees. The object will be rotated 10 degrees. An object rotated with a relative transformation would have been rotated 100 degrees. Relative mode adds or multiplies the new transformation to the existing transformation. The software defaults to absolute transformations. Occasionally, you will find a need for relative, especially when you are working with exact measurements.
relative

Switch the selection button to Relative transformation on the status line, way over on the top right side of the screen. (Sometimes this is hidden if your screen is small, click on the show/hide buttons to expand hidden sections.) When you enter a value in the box for a transformation, such as scale, rotate, or move, the object or component will transform using a relative transformation.



Rebuild Surfaces
This function can clean up unnecessary points or isoparms, it is also very useful for texture mapping. Rebuild Surfaces can help fit texture maps across your surface more evenly.

Use Surfaces->Rebuild->option.jpg

The defaults work pretty well:
Rebuild Type Uniform
Parameter Range 0 to 1
Number of Spans U 4
, Try adjusting this value.
Number of Spans V 4, Try adjusting this value.
Degree U 3 Cubic, Try 1 Linear if you want a faceted object.
Degree V 3 Cubic, Try 1 Linear if you want a faceted object.
Output Geometry Nurbs, Try Poly if you want to convert Nurbs to Poly.
Click Rebuild



Birail
Draw two curves to be used as paths (or tracks), make sure the tracks are the same type, cubic or linear.

Draw one generation curve that will move along the paths. Use point snap or curve snap to line up the generation curves to the paths.

Pick
the generation curve first, and use the shift key to the two paths, all three curves should be selected.

Select Surfaces->Birail 1 Tool

 1 Tool

birail1.jpg
Two paths and a round generation curve.


birail1R.jpg
The result.


Birail will let you to use more than one generation curve so that the shape of the surface can vary across the paths. Birail can also create a new surface between existing surfaces by picking isoparms.

birail2.jpg
Two paths and three generation curves.




Displacement Maps with the Sculpt Geometry Tool
Go to the Modeling Section, this is similar to the Sculpting tools, but also works on NURBS.

Add a shape with a lot of extra geometry (CVs or vertices).

Choose Surfaces->Sculpt Geometry Tool->option.jpg
This works with Poly or NURBS

Choose the Attribute Maps section

Under Import, Click the Import... button
     Choose an image

Look at your geometry, the image distorted it.

Go back to the first Sculpt tab, notice your shape was distorted by the max displacement and push or pull.

Try painting a distortion with one of the brushes, you may need to change the radius.



Attribute Spread Sheet for Render and Tessellation
Use this window to change attributes on multiple objects, for example, change all the objects in you scene to single sided at once.
Choose Window->General Editors->Attribute Spread Sheet
Choose the Render Tab
Click in the field under Double Sided where it reads off
Click in the Double Sided Box to highlight the entire column
Type a 1 for on, 0 equals off.



Component Editor for Poly only Point Position
Use this window to change attributes for components, for example, change the xyz position of mutliple vertices.
Choose Window->General Editors->Component Editor
Choose the Polygons tab
Type in an XYZ value for one of your vertices.
component_editor



Component Coordinates for NURBS and Polygons
When you select the CVs on NURBS or Polygons, you'll see a node in the Channel Box labeled CVs (Click to Show).Click on this
You'll get the position of the selected CVs in local space.
You can also edit the position of the CVs here.
The CVs are labeled by number.
nurbs_coordinates



Make Fillet between NURBS
Make Cylinder: Create ->NURBS primitives ->Cylinder
Make Planer: Create ->NURBS primitives ->Plane
Scale both to desired size.
Pick both NURBS objects
Choose Surfaces -> Surface Fillet -> Circular Fillet

fillet1

fillet2

fillet3

fillet4