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ILookAt Interface
ILookAt Interface
- LookAt
- LookAtItem
- LookAtFrame
- LookAtModel
ILookAt interface gives a simplified way to orient a frame (local axes) in 3D
space. The interface was added for modification of direction of view, or more
precisely orientation of local frame, of a View Point.
Query path: KernelCAD > GetView
> IViewPointArray >
GetAt > IViewPoint
> ILookAt (Persistent View Points).
Query path: KernelCAD > GetView
> IViewPoint > ILookAt (Transient View Point).
See also Concepts of 3D Graphics, Point Of View Sample, Interface List
HRESULT LookAt(DIPoint* point,
DIVect* dirUp)
Parameters
point - [in] Point to look at
dirUp - [in] Vector
to identify up direction
Returns
- DISP_E_PARAMNOTOPTIONAL if point coincides
with location of this frame.
Remarks:
The method will orient the frame, which implements this interface, so that
its z axis points towards point and its y axis points
in direction determined by dirUp. Note that dirUp
does not have to be precise. Normally it is direction (0,1,0) from the floor up.
It is adjusted as appropriate by the software.
The method will fail if point coincides with location
of the frame (location of View Point).
HRESULT LookAtItem(IItem* iItem,
DIVect* dirUp)
Parameters
iItem - [in]
IItem implemented by n item in the model
dirUp - [in] Vector
to identify up direction
Returns:
- DISP_E_PARAMNOTOPTIONAL if center of iItem
coincides with location of this frame.
Remarks:
Call to this method is equivalent to LookAt(point, dirUp), where
point is center of bounding box of the item if the
item has a bounding box or location of the item.
HRESULT LookAtFrame(I3DObject* i3DObject,
DIVect* dirUp)
Parameters
i3DObject - [in]
I3DObject
implemented by the object to be looked at.
dirUp - [in] Vector
to identify up direction
Returns:
- DISP_E_PARAMNOTOPTIONAL if origin of i3DObject coincides with location of this frame.
Remarks:
Call to this method is equivalent to LookAt(point, dirUp), where
point is the origin of the frame.
HRESULT LookAtModel(IModel* iModel,
DIVect* dirUp)
Parameters
iModel - [in]
IModel
interface of the current model.
dirUp - [in] Vector
to identify up direction
Returns
- DISP_E_PARAMNOTOPTIONAL if center of the model
coincides with location of this frame.
Remarks:
Call to this method is equivalent to LookAt(point, dirUp), where
point is center of bounding box of the model.
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