Difference between revisions of "X3D v4.0 CAD Improvements"

Revision as of 07:11, 17 August 2012

These are proposed changes for a future X3D v3.4 Specification under consideration by the X3D CAD Working Group.

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

Improved nodeset

Nodes to add:

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?