Maya provides
limited support for editing the UV texture coordinates of NURBS
surfaces within the UV Texture Editor. Edit
NURBS UV mode is useful for games developers
who use NURBS surface types in games applications and require the
ability to modify an explicit UV set for subsequent export to a
games engine. This feature does not provide support for editing
NURBS UVs for use with texture mapping or image rendering features
within Maya.
Edit
NURBS UV mode creates an explicit and unique UV set for
the NURBS surface. The user switches between the implicit UVs for
the NURBS surface and the explicitly created UV set. It is then
possible to edit the explicit NURBS UVs on a limited basis.
It is recommended that
you create and edit the explicit NURBS UVs only when all editing
and modification of the NURBS surface model is complete. See the
Notes and
Edit NURBS UVs Limitations below.
For more information
on the MELTM commands and flags that
provide this functionality, see the nurbsUVSet, nurbsEditUV commands
in the MEL guide.
To edit UVs for a NURBS surface in the UV
Texture Editor
- In the scene view, select the NURBS surface
that you want to create and edit explicit UVs for texturing.
- Ensure that the construction history
for the NURBS surface is deleted by selecting
Edit > Delete All by Type > History.
Deleting construction
history prior to making any UV edits ensures that subsequent updates
to the node dependency graph do not remove the UV edits you make
to the explicit NURBS UV set. Do this only when you are sure you
will no longer be required to edit the model (Save a copy of the model
that contains construction history in case you need to revert back for
any reason).
- Turn off construction history while you
work on the NURBS UVs using the Construction History
on/off icon on the Status Line.
- Open the UV Texture Editor by
selecting
Edit UVs > UV Texture Editor.
The NURBS UVs that are
implicitly created with the NURBS surface appear in the 2D view
of the UV Texture Editor.
- In the UV Texture Editor, + click
in the 2D view, and select Edit NURBS UV mode
from the marking menu that appears.
A UV set for the NURBS
surface is explicitly created and displayed in the 2D view of the UV
Texture Editor. The NURBS UV set created is based on the
topology of the NURBS surface.
- Change the selection method to UVs by
doing one of the following:
- + click
in the scene view and select Surface UV from
the marking menu.
- + click
in the 2D view of the UV Texture Editor,
and select UV from the marking menu.
- Select the UVs you want to modify in
either the scene view or in the 2D view of the UV
Texture Editor.
- Using the transformation tools from the Toolbox (Move
Tool, Rotate Tool, or Scale
Tool), edit the position of the NURBS UVs in the UV
Texture Editor.
Notes
- Deleting the construction history on
the NURBS surface is a requirement prior to creating and editing
the explicit NURBS UVs. This ensures that updates to the dependency
graph do not overwrite UV edits.
- Modifying the NURBS surface topology
in any way (that is, inserting an isoparm on the NURBS surface)
after the explicit UV set has been modified will overwrite the unique
NURBS UV set. The explicit NURBS UV set will be updated to take
into account the changes to the topology, but any UV modifications
will be lost.
Edit NURBS UVs Limitations
- The explicit UV set created with this
feature is unique for each NURBS surface. That is, unlike polygon
and subdivision surface types, it is not possible to create multiple
NURBS UV sets for a given NURBS surface.
- The Maya renderers (software, hardware,
mental ray for Maya, and so on) do not support explicit NURBS UVs.
They are only capable of rendering the implicit UVs for NURBS.
- Construction history is not supported.
That is, a user should plan their texturing workflow to occur after
all edits and modifications to the model are complete. Changing
the topology of the model after the NURBS UV set has been edited
will overwrite the UV edits whenever the node dependency graph updates.
- UV modification is limited to UV selection
and transformation only (that is, move, rotate, and scale). It is
not possible to select and modify the explicit NURBS UVs by patch
or isoparm. The polygon and subdivision surface UV modification
features do not work with the explicit NURBS UVs.
- UV sharing is not supported. With explicit
NURBS UVs a UV texture coordinate exists for each patch corner on
the surface. A bounding box selection can be used to move interior
NURBS UVs simultaneously.