# OCC 3D Viewer

OCC (Open CasCade) 3D viewer has been developed on the basis of Open CASCADE Technology. This is the default viewer for Geometry Module, providing good representation of construction and transformation of geometrical objects. Only this viewer allows to work with groups and sub-shapes. This viewer can also work in Mesh module, however, it doesn't allow to visualize meshes.

The functions of OCC viewer are available via its Viewer Toolbar. Buttons marked with small downward triangles have extended functionality which can be accessed by locking on them with left mouse button.

- Dump View - exports an object from the viewer in bmp, png, jpg or jpeg image format.

- Show/Hide Trihedron - shows or hides coordinate axes.

- Fit all - allows to select a point to be the center of a scene representing all displayed objects in the visible area.

- Fit area - resizes the view to place in the visible area only the contents of a frame drawn with pressed left mouse button.

- Zoom - allows to zoom in and out.

- Panning - if the represented objects are greater that the visible area and you don't wish to use Fit all functionality, click on this button and you'll be able to drag the scene to see its remote parts.

- Global panning - represents all displayed objects in the visible area.

- Change rotation point - allows to to choose the point around which the rotation is performed

By default the rotation point is located in the Center of the bounding box of an object.

Unchecking Use Bounding Box Center box allows you to define the coordinates of the rotation point manually.

Set to Origin button restores the default rotation point coordinates.

Select Point from View button allows to select the rotation point in the 3D Viewer

- Rotation - allows to rotate the selected object using the mouse.

- These buttons orientate the scene strictly about coordinate axes.

- Reset - restores the default position (isometric) of objects in the scene.

- Memorise view - saves the current position of objects in the scene

- Restore view - restores the saved position of objects in the scene

- Clone view - opens a new duplicate scene.

- Clipping - allows to create cross-section views (clipping planes) of geometrical objects.

- Base point - allows to define the coordinates of the base point for the clipping plane. Click

- Reset - returns the base point to coordinate origin.

- Direction - allows to define the orientation of the clipping plane.

- Invert - allows to select which part of the object will be removed and which will remain after clipping.

- Preview - allows to see the results of clipping in the viewer.