Define Central Projection (3-D)

• Automatic central projection
• Redefine central projection
• Central projection, viewer distance
• Central projection, angle of vision
• Central projection, line of vision

If points of a part lie too close to the viewer or even behind him, the so-called clip plane comes into effect. This is a plane lying perpendicular to the line of vision directly in front of the viewer. For this, HiCAD displays the message Clip central projection: No (1) Cut (2). In (2), the part with the clip plane is cut. In (1), the parts that cut the clip plane are omitted.

Automatic central projection

Views > Projections >Standard AXO > Automatic central projection

HiCAD determines central projection automatically here, choosing the following data:

• The line of vision results from the current projection.
• The spatial centre lies in the centre point of the drawing.
• The angle of vision is 60.987 degrees.
• The viewer distance is calculated from the current screen plane and the angle of vision.

Redefine central projection

Views > Projections >Standard AXO > Redefine central projection

You use this function to define a central projection by entering all required parameters.

1. Define the spatial centre by means of point determination. Right-click to apply the previous spatial centre and press the middle mouse button to apply the midpoint of the drawing.
2. Specify the viewpoint. The line of vision is now defined by means of the line viewpoint-spatial centre.
3. Enter the viewer distance. If you want a parallel projection to be created, choose 0. The viewpoint will then lie at infinity.
4. Specify a point on the horizon. This point determines the position of the x-axis of the screen plane.
5. Enter the angle of vision.

Central projection, viewer distance

Views > Projections >Standard AXO > Central projection, viewer distance

You use this function to define a central projection by specifying the spatial centre and the viewer distance. The line of vision of the current projection will be retained.

Once you have selected the function, HiCAD marks the current spatial centre.

1. Define the spatial centre by means of point determination. Right-click to apply the previous spatial centre and press the middle mouse button to apply the midpoint of the drawing.
2. Enter the viewer distance.

Central projection, angle of vision

Views > Projections >Standard AXO > Central projection, angle of vision

You use this function to define a central projection by specifying the spatial centre and the angle of vision as well as choosing the viewpoint. As all perpendiculars to the active xy-plane remain parallel, this function enables one-point and two-point projections to be created.

1. Define the spatial centre by means of point determination. Right-click to apply the previous spatial centre and press the middle mouse button to apply the midpoint of the drawing.
2. Specify the angle of vision.
3. HiCAD fades in the axis viewpoint-spatial centre and the angle of vision α instead of the crosshairs at the cursor. You can then use the cursor to choose any viewpoint.

Central projection, line of vision

Views > Projections >Standard AXO > Central projection, line of vision

You use this function to create one-point or two-point projections.

1. Define the spatial centre by means of point specification. Right-click to apply the previous spatial centre and press the middle mouse button to apply the midpoint of the drawing.
2. Enter the viewer distance.
   
   If you want a parallel projection to be created, choose 0. The viewpoint will then lie at infinity.
3. Specify the angle of the line of vision with regard to the x-axis.

The horizon results from the xy-plane of the active coordinate system. You can change the position of the xy-plane by defining a local coordinate system.

 Related Topics

Axonometric and Isometric Projection (3-D) • Projection Methods (3-D) • Central projection (3-D)