Snap mode

Function Name :

• SNAP MODE

You can use snap modes to change the behaviour of the digitise point operation.

The snap mode options you can choose and their effect on digitise operations are:

Snap Mode		Result
Plane		The XYZ value is at the intersection of a ray from the camera projected through the cursor location and the viewing plane. That is, the position at the precise coordinates of the cursor. This is the default mode.
Point		Previously known simply as "on" and now as "point", the XYZ coordinates of the closest point (or closest triangle vertex) to the cursor location.
Line		The XYZ value of a point which is exactly on the line between two existing points (consecutive points on the same segment). This is done by finding the position on the line between the 2 points on the segment which has the shortest distance to the location of the cursor.
Triangle		The XYZ value is where the intersection between the ray from the camera projected through the cursor position and the triangle containing the cursor occurs. If the cursor is not inside the bounds of a triangle then the result produced is the same as if snap mode were set to Plane. This mode is very useful for digitising points exactly onto DTM surfaces or solid models.
Drafting		Snapping is performed using a virtual ruler and protractor.
Project selections to plane		Selected points are projected by their position on the active plane. Note: This option is available only if you are digitising and snap mode is set to Point, Line, or Triangle.

Some examples of functions whose behaviour is altered by the use of snap mode are:

• Point Move and Point Insert
• Segment Copy and Segment Move
• String Copy and String Move

Before Surpac version 6.3, you had to exit the function you were using to change snap mode. From version 6.3 onwards you do not need to exit the function to change modes. You can change modes using the drop-down menu on the toolbar, or right-click in Graphics , and choose the new mode from the shortcut menu, and then continue using your function. The right-click shortcut menu also has icon buttons to undo, redo, close the segment, end the segment, digitise a new string, and change to DIGITISER MIDPOINT (if you are using DIGITISER DIGITISE) or DIGITISER DIGITISE (if you are using DIGITISER MIDPOINT). You can also use the following shortcut keys to change between modes:

• 1 - Plane
• 2 - Point
• 3 - Line
• 4 - Triangle
• 5 - Drafting
• CTRL and Z - Undo
• CTRL and Y - Redo
• 0 - DIGITISER CLOSE SEGMENT
• - (minus) - DIGITISER END SEGMENT
• + (plus) - DIGITISER NEXT STRING
• / (forward slash)- DIGITISER MIDPOINT
• . (period) - DIGITISER DIGITISE

Note: Drafting snap mode is available only when you are digitising.

See also

• Drafting mode