In Rhino, the positive direction of the Y-axis is always designated as Project North. You can adjust your project's orientation relative to this inherent North direction using a couple of methods.
Understanding Project North in Rhino
Rhino defines Project North as the direction aligned with the positive Y-axis in the world coordinate system. This means that by default, the 'top' of your model when looking down the Z-axis (in the default Top viewport) aligns with North.
Methods for Setting Project North
Based on standard Rhino workflows and the provided reference, there are two primary ways to effectively change which direction represents North in relation to your building model or project layout:
1. Rotating the Construction Plane (CPlane)
This method involves rotating the coordinate system that you are working on, rather than rotating the model itself.
- How it works: By rotating the Construction Plane (CPlane), you redefine the orientation of the X and Y axes relative to your model. Since the Y-axis dictates North, rotating the CPlane rotates the perceived North direction.
- Using the Command: You can use the
CPlanecommand to manipulate the construction plane.- Type
CPlanein the command line. - Choose the
Rotateoption. - Specify the axis around which you want to rotate (usually Z for rotating horizontally).
- Enter the desired angle of rotation.
- Type
This method keeps your model's world coordinates static but changes your working plane's orientation.
2. Rotating Your Building Geometry
Alternatively, you can rotate your model geometry to align its intended North direction with the positive Y-axis of the world coordinate system.
- How it works: If your building is modeled such that, for example, its facade facing true North is currently aligned with the positive X-axis, you would rotate the entire building model so that this facade aligns with the positive Y-axis.
- Using the Command: Use the standard
Rotatecommand.- Select the geometry you wish to rotate.
- Type
Rotatein the command line. - Specify a center of rotation (often a key point on your model).
- Specify a first reference point or angle.
- Specify a second point or enter the rotation angle to orient your model correctly relative to the world Y-axis.
This method physically rotates your model within the world coordinate system.
Choosing the Right Method
Both methods achieve a similar result – aligning your project with the defined North direction (positive Y-axis).
- Rotating CPlane: Useful when you want to orient your view and working plane to align with a specific direction of your model without changing its world coordinates. This is often used for drafting details oriented to a specific building facade.
- Rotating Geometry: More common when setting up a master site model or preparing geometry for export to other software that expects the main building orientation to align with global axes.
| Method | Command | Affects | Best Used For |
|---|---|---|---|
| Rotate Construction Plane | CPlane |
Working Plane | Drafting on specific building orientations |
| Rotate Geometry | Rotate |
Model | Global site orientation, export preparation |
Understanding that the positive Y-axis is North in Rhino allows you to apply these methods to align your project accordingly.
