Dynamic UCS

With the Dynamic UCS feature enabled, the coordinate system is aligned automatically with the entity under the cursor.

The UCSDETECT system variable controls the supported entity types:

• 1 : faces of 3d Solids (the default)
• 2 : other entity types: point, line, polyline, 2D polyline, 3D polyline, ray, xline, arc, circle, ellipse, spline, text, mtext, solid, 3Dface, trace, block insert, viewport, mline, leader, mleader, hatch, helix, camera, light, section, shape, pdf underlay and image.

UCSDETECT is an integer type with values in the range [-3;3]. The DUCS status bar control allows toggle the feature and to select the supported entity types.

This feature is controlled by system variables.

• The RedHilite_DUCSLocked_Face_Color user preference controls the highlight color for the face to which the Dynamic UCS has been locked by pressing the Shift key.
• The RedHilite_DUCSLocked_Face_Alpha user preference controls the highlight transparency for the face to which the Dynamic UCS has been locked by pressing the Shift key.

To toggle the dynamic UCS

Do one of the following:

• Press the F6 function key.
• Click the DUCS field in the status bar.

Using the Dynamic UCS 

1. With the Dynamic UCS feature active, launch an entity creation command, e.g. Draw.
2. Move the cursor over an entity or 3D solid face.

• The entity or face highlights.
• If ON, the grid is aligned with the hovered entity or face.
• If UCSICON = 3 (On at Origin), the UCS icon displays.
  
  

  Dynamice UCS on other entities

  
  

  Dynamic UCS on 3D solid faces

• The dynamic UCS is oriented depending on how the cursor touches the hovered entity or face, thus providing users a way to manipulate the orientation of the DUCS.
  On 3D solid faces the origin of the DUCS is set to the start point of the solid edge and the X-axis is chosen codirectional to the tangent at the start point of the edge.
  On curved faces, the the X-acis is tangent to the face, the Y-axis lies in the face and the Z-axis is perpendicular to the face.

3. (option) Tap the Shift key to lock the DUCS, which allows you to start drawing outside the hovered entity or face. Tap the Shift key again to unlock the DUCS.
4. Pick a point to start drawing.
5. When the drawing command concludes, the WCS or previously defined UCS is restored.