IMeshTopol(64) Interface
- AddVertex
- RemoveVertex
- AddSimplex
- RemoveSimplex
This interface allows changing structure of the mesh or even build a whole
new meshed surface.
This interface is available only in Pro or Enterprise level products, where
it can be queried from IMesh interface
Methods of this interface requires a call to IModel.Update() or DG Kernel.UpdateSurface() for changes to appear in 3D view
See also Morph sample, IMesh,
Interface List
HRESULT AddVertex(POSN* posnResult)
Parameters
posnResult - [out] - position
of the newly created vertex in the vertex list of the mesh.
Returns
- S_OK in case of
success.
-
- Remarks:
This methods creates a new vertex and inserts it into vertex list of the
mesh. The position of the vertex is returned in posnResult. Note:
it is wrong to assume that the vertex is added at the end of the vertex
list.
HRESULT RemoveVertex(POSN vertex)
Parameters
vertex - [in]
position of the vertex in vertex
list of the mesh.
Return Values
-
- S_OK in case of
success.
-
- Remarks:
As the result the vertex will be removed from the vertex list. Note that this
operation will not remove the adjoined simplexes and normally does not have any
visual effect.
HRESULT AddSimplex(POSN vert0, POSN vert1, POSN vert2, double creaseAngle)
Parameters
vert0, vert1, vert2 - [in]
positions of the vertices, which will become
corners of the simplex.
creaseAngle - [in] - Crease angle in degrees for automatic handling of normals at vertices of the newly added simplex.
Return Values
-
- S_OK in case of
success.
-
- Remarks:
Will add a new simplex at the end of the simplex list. The simplex will have
vertices identified by vert0, vert1 and
vert2 as its corners.
creaseAngle (degrees) is used to determine how normal at a corner of the
new simplex should be handled. The algorithm is: First the normal vector of the face of the
simplex is calculated. Than normal, which has the smallest angle with the face
normal is found at the corner vertex. If the smallest angle is less than creaseAngle
the nearest normal is averaged with the face normal. In the opposite case the
face normal is added as a new normal at the vertex.
Set creaseAngle to a negative number to skip normal modifications
In practice, when creaseAngle is non-negative, it should never be zero and rarely less than 10.
It should be less than 180 and rarely greater than 90. Low values of creaseAngle reduce performance and increase memory consumption.
It is recommended to experiment with this parameter. Setting creaseAngle too high values causes geometrically sharp edges
not to look sharp on the screen.
It is more efficient to add any simplexes after coordinates of all vertices
have been calculated. Otherwise calculated normals will be incorrect, which
result in incorrect lighting of the object. To recalculate all normals in the
mesh call IMeshMods.FixupNormals
method.
HRESULT RemoveSimplex(POSN simplex)
Parameters
simplex - [in]
position of the simplex in simplex
list of the mesh.
Return Values
-
- S_OK in case of
success.
-
- Remarks:
Removes a simplex from the mesh. This operation does not remove vertices of
the simplex.
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