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Contents, Programmers Guide, World Representation, 2D Content Processing, Content Validation

Content Validation

The following general validation constraints are applied to content being processed (in addition to any content processing option specific validation):

(These validation constraints relate directly to the validation constraints applied to PathEngine's internal 3D base mesh format.)

Coordinate range

The coordinates for vertices of the mesh must be within the range supported by PathEngine.
(See PathEngine Coordinates for details.)

Empty meshes not supported

The mesh resulting from content processing must consist of one or more triangular faces.

Face constraints

Each face must have non-zero area.
The vertices for each face must run clockwise as seen from above.
(Put another way, each vertex must lie on the right of the line formed by the previous two, as seen from above.)
This validation constraint can relate to the mesh scale being used.
If the scale being used is too low then a lot of sliver faces with zero area can be created.

In practice these kinds of sliver faces are now often processed automatically by the automatic vertical edge collapse feature.

Connectivity constraints

The connectivity between faces (as implied by the way that vertices are shared between faces) must be one-to-one.
The general form of non-manifold meshes is not supported.
(But see Non Manifold Resolution.)

Validation error attributes

Content validation errors will be reported through PathEngine's error handler mechanism.
The following attributes may be set, where relevant, to provide feedback about faces or vertices in the original content that relate to the error:

'meshPart' - this is an index into the set of face vertex objects passed into the content processing functionality.
The attributes below then provide face or vertex indices relating to this object.

'faceIndex', 'faceIndex1', 'faceIndex2', 'vertexIndex', 'vertexIndex1', 'vertexIndex2' - face or vertex indices into the object specified by 'meshPart'.

It is very important to provide this feedback for content creators in order to enable validation errors to be processed quickly and easily.
The Max exporter handles these errors by setting the sub-object selection sets for the relevant object.

Documentation for PathEngine release 6.03 - Copyright © 2002-2021 PathEnginenext: Vertical Discontinuities