[x3d-public] Fwd: Re: mantis 1252, PointProperties node specification and inclusion of Normal data

[Don Brutzman]

These changes got applied to XML Schema/DTD and X3DUOM for X3D4, also compiles satisfactorily under X3DSAIL.

-------- Forwarded Message --------
Subject: Re: mantis 1252, PointProperties node specification and inclusion of Normal data
Date: Thu, 11 Jun 2020 11:22:02 -0700
From: Don Brutzman <brutzman at nps.edu>
Organization: Naval Postgraduate School (NPS)
To: Vincent Marchetti <vmarchetti at kshell.com>
CC: Richard F. Puk <puk at igraphics.com>, Nicholas Polys <npolys at vt.edu>

FYI we came up with the following addition to the mantis issue.  We also applied these changes to draft X3D4 specification.  Looks good.

======================================
Change summary for Normals:

Add the following to LineSet, IndexedLineSet, PointSet

   SFNode [in,out] normal NULL [X3DNormalNode]

with prose

"No effect on rendering behavior is defined for data specified by the normal field. Rendering techniques that utilize normal information to refine presentation of geometry are allowed but not required."

Considered but not included:

NOTE. Rendering of 3D scan data may choose to apply normal information for mesh visualization, culling or other purposes.

----

11.4.10 Normal node:

"This node defines a set of 3D surface normal vectors to be used in the vector field of some geometry nodes (EXAMPLE IndexedFaceSet and ElevationGrid). This node contains one multiple-valued field that contains the normal vectors. Normals shall be of unit length."

Interestingly that is the entire definition of the node.

Replace first sentence as follows, keeping original second and third sentences above.

"This node defines a set of 3D direction vectors to be used for the normal field of some geometry nodes (EXAMPLE IndexedFaceSet, IndexedLineSet, LineSet, PointSet, and ElevationGrid). The term 'normal' is common usage to indicate direction vectors, even though the direction vectors might not necessarily indicate perpendicularity."

---

Level support table: note /normal/ optionally supported for LineSet, IndexedLineSet, PointSet under level 1.

=====================================

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman