PlaneSliceModelVisual3D(ModelVisual3D, Transform3D, ModelVisual3D, ModelVisual3D) Method

public void SliceModelVisual3D(
	ModelVisual3D modelVisual3D,
	Transform3D parentTransform,
	out ModelVisual3D frontModelVisual3D,
	out ModelVisual3D backModelVisual3D
)

Parameters

modelVisual3D  ModelVisual3D

ModelVisual3D

parentTransform  Transform3D

Transform3D that is added to the modelVisual3D (null by default)

frontModelVisual3D  ModelVisual3D

Out parameters as ModelVisual3D for front models

backModelVisual3D  ModelVisual3D

Out parameters as ModelVisual3D for back models

SliceModelVisual3D slices the 3D models defined by ModelVisual3D with this Plane and creates two new ModelVisual3D objects: one with models that are in front of the plane (in the direction of plane's Normal vector) and one with models in the back of the plane. The models that are fully in front (or in back) of the Plane are not changed (the same instances are used). The models that intersect the Plane are sliced and new models are created from them.

Note for using with textured objects: SliceModelVisual3D correctly calculates sliced TextureCoordinates, but to show the texture correctly, the ViewportUnits on ImageBrush needs to be set to BrushMappingMode.Absolute. It should not be set to BrushMappingMode.RelativeToBoundingBox (a default value in WPF). In case of RelativeToBoundingBox, both sliced parts of the 3D model will still show the whole texture).

Reference