DG Kernel (ActiveX) Documentation


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ILook Interface

Translate
Rotate
Zoom
ZoomEx
GetViewingVolume
SetViewingVolume

ILook interface gives programmatic access to functionality equivalent to rotation of the model with the mouse or using zoom in/out in DInsight applications. ILook does not change nor position nor geometry of any objects in the model. It affects only point of view and the current Viewing Volume. Viewing Volume is the 3D space which is visible in the window of the control. ILook can be retrieved from IView interface ( by using QueryInterface in C++ or coercing the reference to ILook type in Visual Basic).

See also Cannon Sample, Interface List


HRESULT Translate( double vx, double vy, double vz )

Parameters

vx,vy,vz- [in] - translation vector

Returns

S_OK in case of success.
Remarks:

As the result of call to this method the model will appear translated on the screen in the direction of the translation vector. vx and vy values are translation along the horizontal and vertical screen directions correspondently. Normally vz is set to zero. vz will have any effect only if the model falls outside the viewing volume, in which case the model either will appear clipped or will disappear altogether. 


HRESULT Rotate( double angle, double vx, double vy, double vz )

Parameters

angle - [in] angle in degrees by which the current viewing point will be rotated (can be negative).

vx,vy,vz- [in] - axis around which the viewing point will be rotated

Return Values

S_OK in case of success.
Remarks:

Call to this method will change the current point of view in such way that the model will appear rotated  by angle angle around vector with coordinates (vx, vy, vz) in the global axes.


HRESULT Zoom( double scale )

Parameters

scale - [in] value of zoom. If zoom = 2.0 the model will appear twice as big on the screen. If zoom is less than 1.0 the model will appear contracted otherwise it will appear expanded.

Return Values

S_OK in case of success.
 
Remarks
 
Allows programmatically access zoom in/out functionality of the control. Zoom is performed respectively to the center of the current Viewing Volume..

HRESULT ZoomEx( double scale, double centerx, double centery, double centerz )

Parameters

scale - [in] value of zoom. If zoom = 2.0 the model will appear twice as big on the screen. If zoom is less than 1.0 the model will appear contracted otherwise it will appear expanded .

centerx, centery, centerz - [in] coordinates of point with respect of which the model will appear expanded or contracted. The coordinates are relative to the Eye Frame

Return Values

S_OK in case of success.

Remarks:
 
The method allows programmatically access zoom in/out functionality of the control. To obtain Eye Frame coordinates of a point use IFrameEx as described in Global and eye coordinate systems topic.

HRESULT GetViewingVolume( int nAxis, double *pdMin, double *pdMax )

Parameters

nAxis - [in] zero based index of the axis. 0 - horizontal direction, 1 - vertical direction, 2 - depth (see remarks for SetViewingVolume method)

pdMin,pdMax - [out] - minimal and maximal values of nAixs-coordinate of the current Viewing Volume.

Return Values

S_OK in case of success.

Remarks:
 
Call to retrieve the current viewing volume (See remarks for the next method). Allows programmatically identify part of 3D space which is currently displayed.

HRESULT SetViewingVolume( int nAxis, double dMin, double dMax )

Parameters

nAxis - [in] zero based index of the axis. 0 - horizontal direction, 1 - vertical direction, 2 - depth ( see remarks )

dMin, dMax - [in] - new range of Viewing Volume in nAxis direction.

Return Values

S_OK in case of success.

Remarks:
 
Viewing Volume is the part 3D space which is currently displayed in the window of the control. Viewing Volume is a rectangular box, four sides of which are orthogonal to the plane of the screen and extensions of which intersect plane of the screen at the screen edges. Dimensions of the Viewing Volume are determined in screen axes.  x axis  of the screen axes (axis 0) is directed horizontally to the right. y  axis (axis 1) is directed vertically up.  z axis directed from the screen toward the viewer. 
 
Reducing  the Viewing Volume to contain only a particular object of the model is equivalent to setting focus on the object. Everything else will be cut off. Expanding the Viewing Volume allow to display more on the screen, which is some sort of zoom out. Generally speaking changing Viewing Volume is equivalent to combination of zoom and translation operations.

Note that dimensions of the Viewing Volume in z direction (depth coordinate) are always finite. If model falls out of the z extents of the Viewing Volume it will appear clipped at furthest (dMin) or nearest (dMax) side of the Viewing Volume.