Difference between revisions of "X3D v4.0 CAD Improvements"
From Web3D.org
(→X3D CADInterchange Profile: add nodes) |
(→Improved nodeset: node links) |
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Nodes to add: | Nodes to add: | ||
| − | + | [http://www.web3d.org/files/specifications/19775-1/V3.3/Part01/components/networking.html#Anchor Anchor]] | |
| − | + | * Needed for description and Viewpoint selection (level 1) | |
| − | + | * Also needed for linking to other networked resources (level 2) | |
| − | + | [http://www.web3d.org/files/specifications/19775-1/V3.3/Part01/components/networking.html#Inline Inline] | |
| − | + | * Needed for modular re-use of CAD-model files | |
| + | * Concern: possibility of short-circuiting CAD product structure within an extended file. Related future specification change: | ||
| − | + | Any node children created by Inline, ProtoInstance or Script (via a createX3D method ) | |
| − | + | need to follow the CAD product structure defined by their parent nodes. | |
| − | need to follow the CAD product structure defined by their parent nodes. | + | |
| − | + | [http://www.web3d.org/files/specifications/19775-1/V3.3/Part01/components/shape.html#FillProperties FillProperties] | |
| − | + | * Definitely needed for proper display to distinguish different parts or selected parts. Related to definition of component levels in the profile. | |
| − | + | [http://www.web3d.org/files/specifications/19775-1/V3.3/Part01/components/navigation.html#OrthoViewpoint OrthoViewpoint] | |
| − | + | * The primary purpose of OrthoViewpoint is to support common use cases for CAD model viewing. (This node was probably added after the initial CAD profile.) | |
| − | + | [http://www.web3d.org/files/specifications/19775-1/V3.3/Part01/components/navigation.html#ViewpointGroup ViewpointGroup] | |
| − | + | * Allows nesting of Viewpoints within models without exploding or overloading the Viewpoint list, which is an essential tool for user navigation. | |
Revision as of 14:29, 17 August 2012
These are proposed changes for a future X3D v3.4 Specification under consideration by the X3D CAD Working Group.
Contents
X3D CAD Component
- Existing specification: X3D v3.3 CAD Geometry Component
Child-node relationships more explicit
- Many parent-child node relationships are vague, leading to difficulty deciding which children are allowed. For example, X3DGroupingNode is implemented by many candidate nodes.
- These relationships are strictly captured in the X3D DTD and X3D Schema, with further support in X3D Schematron
- In order to best support model export and interoperability, the child nodes are limited to those listed in the CADInterchange Profile
Proposed specification prose: needed.
Tesselation consistency
- Exporters can significantly reduce file size using primitive-geometry nodes (e.g. Cylinder, Disk2D, etc.)
- Tesselation quality is not strictly defined in X3D
- In order to match polygonal tessellation strictly and avoid "cracks" between adjactent geometry, some form of association is needed (similar to the NURBSet node)
- CADPart semantics can be improved to include this constraint
Proposed specification prose: needed.
X3D CADInterchange Profile
- Existing specification: X3D v3.3 CADInterchange profile
- Primary discussion: revising CADInterchange profile email thread
Improved nodeset
Nodes to add:
- Needed for description and Viewpoint selection (level 1)
- Also needed for linking to other networked resources (level 2)
- Needed for modular re-use of CAD-model files
- Concern: possibility of short-circuiting CAD product structure within an extended file. Related future specification change:
Any node children created by Inline, ProtoInstance or Script (via a createX3D method ) need to follow the CAD product structure defined by their parent nodes.
- Definitely needed for proper display to distinguish different parts or selected parts. Related to definition of component levels in the profile.
- The primary purpose of OrthoViewpoint is to support common use cases for CAD model viewing. (This node was probably added after the initial CAD profile.)
- Allows nesting of Viewpoints within models without exploding or overloading the Viewpoint list, which is an essential tool for user navigation.
Nodes to remove:
Renaming necessary?
Extensive changes to this profile may make backwards compatibility difficult. X3D profiles do not support a concept of level as components do.
- Should the profile be renamed for clarity, maintaining the old profile separately?
- Alternatively should the old profile be deprecated?
- Is there a better way to express this evolution, simply noting that the v3.4 profile is different?
