[x3d-public] Add quality parameter to Geometry3D primitives

Don Brutzman brutzman at nps.edu
Sat Feb 1 13:11:00 PST 2020

On 1/24/2020 8:16 PM, Spec Feedback wrote:
> -- Submitter indicates that this comment may be public: *Yes* --
> Comment on 19775-1: Abstract X3D Definitions - V3.3
> 13 Geometry3D
> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/geometry3D.html#Nodereference

not finding any mention of polygonal refinement/resolution/quality for primitive geometry in this component.

> -----------------
> Browser. PrimitiveQuality ... (as X_ITE does)
>    OR
> put a field on each primitive:
>    like X3DOM subdivision='32' for Cone and Cylinder
> subdivision='24,24' for Sphere
> -----------------
> Submitted on Friday, 2020,  January 24 - 8:16pm
> by  (Nicholas F Polys )
> See: https://www.web3d.org/node/1694/submission/3849

Entered as

* Mantis issue 1280: Add quality parameter to Geometry3D primitives


* Part 2: Scene access interface (SAI), 6 Services reference, 6.3.21 getRenderingProperties
   Properties listed: Shading,MaxTextureSize,TextureUnits,AntiAliased,ColorDepth,TextureMemory
   "The user shall not be able to directly effect the rendering properties of the browser by modifying the properties returned by this service."

Xj3D has added Browser property primitiveQuality.  This is helpful if using Browser class within an SAI script, but such properties are rarely used in practice, and are not simply available as settable parameter in a plain scene under Interchange/Interactive Profiles where the nodes are allowed.

* BrowserConfig.java
     /** Primitive geometry quality. "low"|"medium"|"high". Default "medium". */
     public String primitiveQuality;


a. Historically no mention of polygonal quality was made in VRML/X3Dv3.0 because browser implementers wanted flexibility to tessellate as they see fit.

b. Since no mention of rendering quality appears to be made in the specification, one might surmise that the geometry is considered perfect mathematically and should always be smooth.

c. In practice many/most players create a one-time mesh and then do not consider user proximity or perceived fidelity.  This makes primitive rendering very efficient.

d. If added to the specification, definition prose should include (or allow definition of) polygonal resolution

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

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